FREEWAYS CONGESTION HOT SPOT PROBLEM & …media.metro.net/projects_studies/I605/605_07_part1.pdfLimits and logical terminus of the congestion problem area . An effectiveness analysis

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Page 73 Metro and GCCOG SR-91/I-605/I-405 Congestion Hot Spots

7.0 FREEWAYS CONGESTION HOT SPOT PROBLEM & IMPROVEMENT PROJECT ANALYSIS & DEFINITION

7.1 INTRODUCTION & METHODOLOGY

Congestion “hot spot” problem locations have been assessed using the data and analysis that was developed and presented in the Congestion Analysis Report. The information used to assess the congestion problems include existing speed profile data (Caltrans PeMS), 2035 No-Build level of service results from the Highway Capacity Manual (HCM) analysis, 2035 No-Build level of service results from the travel demand model, existing accident history, plus the Combined Congestion Score which includes a combination of these data sources to generate a numerical value representing a common comparison of congestion through freeway segments spanning from interchange to interchange. A critical engineering review of existing geometric conditions and deficiencies along each freeway corridor is also used to help identify the specific congestion locations. All of this data is then used to identify the magnitude and specific congestion characteristics of these “hot spots.” All analyses have been based on maintaining existing non-standard lane and shoulder configurations with new lane widening proposed at current lane and shoulder width standards. The effects of full standard widening may change the assessment of congestion problem areas, potential solutions and the various impacts of those solutions related to right of way, environmental considerations and cost. To assess the larger footprint of using full standards, a line is included on the conceptual geometric plans to show the extent of additional widening that would be required. Full standards will be evaluated in any subsequent work. The congestion hot spot analysis is presented by individual freeway corridor in the direction of travel to enable the reader to follow and track the analysis in the direction they would be driving on the freeway. A map and congestion explanation for each congestion hot spot location is included herein outlining the following items:

Type, characteristic, “root cause” and specific details of the congestion problem;

Contribution (exacerbation) of adjacent congestion problem areas on the congestion area being examined; and

Limits and logical terminus of the congestion problem area An effectiveness analysis of components of Concepts A, B and C, as well as No-Build, has been performed to determine how each concept improves (or provides a solution for) the specific congestion problem area, and the magnitude (or extent) of the congestion improvement. The magnitude (or extent) of the improvement and the effectiveness (as specific as possible) of the “solutions” will be based upon the following elements: 1) the volume of traffic that benefits from the improvement, 2) improvement of a high accident location, 3) complete or partial improvement of the congestion problem, 4) interaction of this congestion problem with those of adjacent congestion problem areas, 5) preliminary cost of the congestion problem solution, and 6) general cost/benefit assessment. Information is also provided for right of way impact

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assessment and environmental considerations and issues to provide an additional basis for qualitative assessment. While no further traffic model runs and HCM traffic analyses were performed for this Feasibility Report, other traffic model runs and associated data compiled as part of the Congestion Analysis Report and the Traffic Model Run Summary Report were used to support qualitative assessments of congestion hot spots in specific locations. As discussed in Section 5.0, the choice of the geometric improvement was not significantly affected by the results of the other model runs – the geometric improvement is mostly needed with or without the other multi-modal improvements. However, in other locations the other traffic model runs were consulted as needed to assess the need for specific improvements on a case-by-case basis. This was assessed through a qualitative analysis consisting of a review of model output data such as change in volume on the mainline segments and change in speeds from the model due to the other (non-geometric improvements).

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PostMile SR-91 Location 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

15.229 ORANGETHORPE 68 66 66 66 70 68 50 38 53 56 62 64 66 66 65 61 58 48 63 68 69 69 69 69

14.138 183RD 65 63 64 63 65 63 46 29 44 51 56 59 60 60 58 52 50 40 55 64 65 65 65 65

13.498 ARTESIA 66 63 63 63 66 65 44 25 38 49 56 59 61 61 58 50 46 35 54 65 66 67 66 66

13.398 SHOWMAKER 67 65 65 65 68 66 44 25 40 50 57 60 62 63 60 51 48 37 55 66 67 67 67 67

13.058 BLOOMFIELD 66 64 64 64 67 66 42 24 35 47 56 59 61 62 57 47 43 32 50 65 67 67 67 67

12.698 NORWALK 2 64 62 62 62 63 62 45 34 41 49 55 56 58 59 56 50 47 42 51 62 64 64 63 63

12.498 NORWALK 1 66 64 64 64 67 64 42 28 34 44 52 55 58 59 54 46 45 40 49 63 66 66 66 66

12.208 PIONEER 2 66 64 64 64 66 63 41 28 33 42 50 53 55 57 52 45 44 39 47 61 66 66 66 67

11.958 PIONEER 1 66 65 65 65 69 66 51 38 40 49 54 57 58 59 57 53 54 52 55 64 67 67 67 68

11.368 STUDEBAKER 64 61 62 63 64 62 50 30 37 49 52 52 53 53 54 54 56 56 56 59 59 60 61 62

10.798 W OF 605 63 58 58 60 63 62 47 24 34 51 55 55 56 56 57 58 59 60 58 60 60 61 61 61

10.218 CALIFORNIA 69 67 67 68 71 68 45 22 31 54 60 60 61 62 62 63 65 65 64 67 69 70 70 70

9.758 BELLFLOWER 2 67 65 65 66 69 66 45 24 31 54 59 57 57 56 56 57 59 62 63 66 67 67 67 67

9.538 BELLFLOWER 1 62 59 59 60 64 60 41 23 29 49 54 54 55 55 55 55 57 58 57 60 61 62 62 61

9.218 CLARK 57 52 52 52 57 57 41 23 29 50 54 54 55 55 56 56 58 59 57 58 58 59 58 56

8.648 LAKEWOOD 2 68 67 67 68 72 67 46 25 30 56 60 62 63 64 65 65 66 67 67 70 71 71 71 70

8.548 LAKEWOOD 1 62 57 57 59 64 63 46 27 32 53 56 56 56 56 56 57 60 62 62 63 62 63 62 60

7.998 DOWNEY 1 63 61 62 64 65 60 49 35 34 51 54 55 56 57 57 57 59 59 59 61 62 62 61 61

7.508 PARAMOUNT 73 73 74 76 80 79 72 45 41 68 69 70 71 71 72 73 74 75 75 75 75 76 75 74

7.008 CHERRY 69 67 68 70 72 69 62 36 30 60 62 63 65 66 66 67 69 70 69 70 70 70 69 68

6.568 ORANGE 68 66 67 68 70 67 59 38 35 58 61 61 62 63 64 64 66 67 68 68 69 70 69 69

6.198 ATLANTIC 2 68 68 69 70 72 71 65 41 38 62 65 65 66 67 67 68 69 70 70 71 70 70 70 69

5.778 ATLANTIC 1 62 58 59 61 64 60 51 22 23 53 57 57 57 58 58 59 60 61 61 61 61 61 61 61

5.028 LONG BEACH 71 70 70 72 74 69 52 25 25 50 57 57 58 59 60 62 64 67 68 69 70 72 72 72

Hour of the day

7.2 SR-91 WESTBOUND CONGESTION HOT SPOT PROBLEM ANALYSIS

SUMMARY

The location and duration of existing congestion along SR-91 westbound (WB) are illustrated in using the PeMS Speed Contour Exhibit in Figure 9. Segment speeds less than 25 mph are shown as red, 25 to 35 mph are shown as orange/brown. Less than 35 mph is typically used to define severe congestion on most maps and reports showing freeway speeds. Thus, both the red and orange/brown colors indicate significant congestion/delay on the freeway systems, and the yellow segments indicate slowing and areas that are nearing the point of significant congestion/delay. Figure 9 shows that existing congestion occurs throughout the entire study area for over three hours in the AM and east of I-605 for two hours in the PM.

FIGURE 9: PEMS SPEED CONTOUR FOR WB SR-91

Eleven locations have been documented as the areas that represent significant congestion problem areas for purposes of detailed analysis. The following discussion and the corresponding Figures 11-12 display the eleven congestion problem hot spot locations along with a description of the congestion issues at each location. The eleven hot spot locations for SR-91 WB are as follows (labeled 91 WB-1 through 91 WB-11 for hot spot locations 1 through 11):

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91 WB-1: Artesia Boulevard to Norwalk Boulevard

91 WB-2: Norwalk Boulevard to Pioneer Boulevard

91 WB-3: Pioneer Boulevard to N/S 605 Connector Ramp Diverge

91 WB-4: N/S 605 Connector Ramp Diverge

91 WB-5: S 605 – W 91 Connector Ramp Merge

91 WB-6: Clark Avenue to Bellflower Boulevard

91 WB-7: Mainline Lane Addition at Downey Avenue

91 WB-8: Paramount Boulevard to Cherry Avenue

91 WB-9: Atlantic Avenue Off-Ramp Diverge to N/S 710 Connector Ramp Diverge

91 WB-10: N 710 – W 91 Connector Ramp/Atlantic Avenue On-Ramp Merge

91 WB-11: S 710 – W 91 Connector Ramp Merge to Long Beach Boulevard Based on a careful review of the detailed congestion problem analysis results, each of these locations is determined to experience congestion that warrants some type of improvement and is thus designated as a congestion hot spot. The eleven specific congestion locations are further described in terms of why they were identified as hot spots, including a summary of the analysis results, plus descriptions of the causes of congestion at each location. It has also been determined that although SR-91 WB east of Bloomfield Avenue to the Los Angeles/Orange county line does experience congestion, it is largely the result of downstream congestion west of Bloomfield Avenue that spills back into this segment and not specific freeway deficiencies.

CONGESTION HOT SPOT 91 WB-1

Location: Artesia Boulevard to Norwalk Boulevard

Performance Measures

PeMS Speed Data: The freeway mainline experiences extremely slow speeds with current average speeds of less than 35 mph during the AM peak and during the PM peak.

2035 No-Build Level of Service: The level of service indicates extreme congestion during both AM and PM peak periods. This is based on the 2035 No-Build HCM LOS E in the AM peak period and LOS F in the PM peak period for the mainline weave. The model V/C LOS D in the AM peak period and LOS F in the PM peak period also indicates extreme congestion.

Accident History: Accident history does not exceed statewide average by 30 percent or more.

Congestion Score: This location received a combined congestion score of 7 in the AM and 9 in the PM indicating severe congestion from multiple causes.

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Cause of Congestion

Westbound SR-91 volumes begin to increase (causing slow down and congestion) in the vicinity of the Bloomfield Avenue entrance ramp. Upstream entrance ramp volumes (516 AM/ 723 PM) are greater than exit ramp volumes (294 AM/421 PM) resulting in mainline congestion. A short weaving distance of approximately 1,000 feet between Bloomfield Avenue and Norwalk Boulevard and between Norwalk Boulevard and Artesia Boulevard contributes to congestion in this area. In the vicinity of Bloomfield/Artesia is the first overhead sign indicating the I-605 connector is 1 ¾ mile ahead. Due to short spacing of the arterial street interchanges from this point to the I-605, some WB 91 vehicles heading to NB 605 will start moving to the right lanes to get positioned to exit. Congestion at this location is also interrelated to Hot Spot WB-2, WB-3 and WB-4.


Location: Norwalk Boulevard to Pioneer Boulevard


PeMS Speed Data: The freeway mainline experiences extremely slow speeds with current average speeds of less than 35 mph during the AM peak and 35 to 45 mph during the PM peak.

2035 No-Build Level of Service: The level of service indicates extreme congestion during both AM and PM peak periods. This is based on the 2035 No-Build HCM LOS E in the AM peak period and LOS E in the PM peak period for the mainline weave. The model V/C LOS E in the AM peak period and LOS F in the PM peak period also indicates extreme congestion.

Accident History: Accident history exceeds statewide average by 30 percent or more at this location with a predominance of rear end accidents.

Congestion Score: This location received a combined congestion score of 10 in the AM and PM peak periods indicating severe congestion from multiple causes.

Cause of Congestion

The mainline volumes (6750 AM/8081 PM) approach full capacity. A short weaving distance of approximately 1,000 feet between Norwalk Boulevard and Pioneer Boulevard contributes to congestion in this area. Overhead signs continue in this area indicating the I-605 connector is ahead. Due to short spacing of the arterial street interchanges from this point to the I-605, WB 91 vehicles heading to NB 605 continue moving to the right lanes to get positioned to exit. Congestion at this location is also interrelated to Hot Spot WB-1, WB-3 and WB-4.

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Location: Pioneer Boulevard to N/S 605 Connector Ramp Diverge Performance Measures

PeMS Speed Data: The freeway mainline experiences extremely slow speeds with current average speed of 35 mph during the AM peak and 45-55 mph during the PM peak.

2035 No-Build Level of Service: The level of service indicates extreme congestion during both AM and PM peak periods. This is based on the 2035 No-Build HCM LOS E in the AM peak period and LOS F in the PM peak period for the mainline weave. The model V/C LOS D in the AM peak period and LOS F in the PM peak period also indicates extreme congestion.

Accident History: Accident history exceeds statewide average by 30 percent or more at this location with a predominance of rear end accidents.

Congestion Score: This location received a combined congestion score of 10 in the AM peak period and 9 in the PM peak period indicating severe congestion from multiple causes.

Cause of Congestion

The high 2035 No-Build volume (791 AM / 685 PM) of traffic entering the mainline at Pioneer Boulevard and exiting to I-605 (3208 AM / 3421 PM) and mainline weaving distance of approximately 2,400 feet results in congestion in this segment between Pioneer Boulevard entrance and I-605 exit. Due to short spacing of the arterial street interchanges from this point to the I-605, any remaining WB 91 vehicles heading to NB 605 move to the right lanes to get positioned to exit. Congestion at this location is interrelated to Hot Spots WB-1, WB-2 and WB-4. As a result, westbound SR-91 volumes typically back up at this location on a daily weekday basis to the east past WB-1 and WB-2.


Location: W 91 – N/S 605 Connector Ramp Diverge Performance Measures

PeMS Existing Speed Data: The freeway mainline experiences extremely slow speeds with current average speeds of less than 35 mph during the AM peak period. During the PM peak period the speeds are between 45 and 55 mph which also is an indication of congestion.

2035 No-Build Level of Service: The level of service indicates extreme congestion during both AM and PM peak periods. This is based on the 2035 No-Build HCM LOS E in

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the AM peak period and LOS F in the PM peak period for the mainline weave. The model V/C LOS E in the AM peak period and LOS F in the PM peak period also indicates extreme congestion.

Accident History: Accident history exceeds statewide average by 30 percent or more at this location, which is an indication of congestion at this location.


Cause of Congestion

The 2035 No-Build freeway mainline volumes (7233 AM/8342 PM) are approaching full capacity. The high 2035 No-Build volume (3208 AM / 3421 PM) approaches capacity of the two-lane WB 91-N/S 605 connector ramp and the 2035 No-Build volume (2199 AM / 2126 PM) exceeds capacity of the one lane connector to NB 605.

The weaving distance of 2,400 feet between the Pioneer Boulevard entrance ramp (2035 No-Build volume 791 AM/685 PM) and the two lane N/S 605 connector ramp exit (3208 AM / 3421 PM) is not sufficient for the high volume of weaving vehicles.

The two lane connector ramp splits one lane to SB 605 and one lane to NB 605. The high volume of NB 605 traffic exceeds the capacity of a one lane ramp which causes backup that affects WB 91 operations upstream of this point. The NB 605 connector transitions to two lanes shortly after the one lane diverge movement, allowing the traffic congestion to disperse on the NB 605 connector downstream of this point.

Nonstandard existing shoulder widths (2 feet LT and 8 feet RT) and non-standard existing superelevation rate (6-8%) on the N/S 605 connector ramp also contribute to reduced capacity and congestion at this location.

As a result of the congestion described above, the westbound SR-91 volumes typically back up to the east at this location on a daily weekday basis past WB-1, WB-2 and WB-3.


Location: S 605 – W 91 Connector Ramp Merge


PeMS Existing Speed Data: The freeway mainline experiences extremely slow speeds with current average speeds of less than 35 mph during the AM peak period. During the PM peak period the speeds are 45-55 mph.

2035 No-Build Level of Service: The level of service indicates congestion during both AM and PM peak periods. While the 2035 No-Build HCM of LOS C/D in the AM and PM peak indicates moderate congestion, the model V/C LOS E in the AM peak period and LOS E in the PM peak period indicates extreme congestion.

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Accident History: Accident history exceeds statewide average by 30 percent or more at this location with a predominance of accidents hitting a fixed object.


Cause of Congestion

The high 2035 No-Build volume (1884 AM / 2267 PM) exceeds the capacity of the two-lane ramp that merges to one-lane prior to the entrance into the mainline, which also has high volumes (5510 AM/6656 PM). Nonstandard existing left shoulder width of 2 feet and nonstandard existing 8 percent superelevation on the connector ramp also contribute to reduced capacity and congestion at this location.


Location: Bellflower Boulevard to Clark Avenue


PeMS Speed Data: This segment experiences extremely slow mainline speeds with current average speed of less than 35 mph during the AM peak period. During the PM peak period, speeds are greater than 55 mph, indicating that the congestion issue based on speed measurements occurs only during the AM peak period.

2035 No-Build Level of Service: The level of service analysis indicates extreme congestion during both the AM and PM peak hours. This is based on the 2035 No-Build HCM LOS F in the AM peak hour and LOS F in the PM peak hour. The model V/C is LOS F in the AM peak hour and LOS F in the PM peak hour.


Congestion Score: This segment experiences a combined congestion score of 9 in the AM peak period, indicating severe congestion from multiple causes, and 6 in the PM peak period, indicating moderate congestion problems.

Cause of Congestion

The high 2035 No-Build volumes on the Bellflower Boulevard on-ramp (1281 AM / 758 PM) and the mainline (7353 AM / 7842 PM) contribute to congestion. The Clark Avenue off-ramp (268 AM / 556 PM) has moderate volumes.

A short weaving distance of approximately 650 feet exists between the Bellflower Boulevard on-ramp and the Clark Avenue off-ramp. This creates an operational issue that backs up westbound traffic due to the very short weaving distance in combination with the large volume of vehicles using the Bellflower Boulevard on-ramp and the

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mainline. For instance, the high volumes entering the freeway on the Bellflower Boulevard on-ramp are required to weave over one lane to enter the freeway. Clark Boulevard is a half-diamond (partial) interchange, with ramps only on the easterly side.


Location: Mainline Lane Addition at Downey Avenue


PEMS Speed Data: The segment immediately upstream of the lane addition at Downey Avenue experiences extremely slow speeds with current average speeds of less than 35 mph during the AM peak and over 55 mph in the PM peak, indicating that the congestion issue based on speed measurements occurs only during the AM peak period.

2035 No-Build Level of Service: The level of service analysis indicates extreme congestion during both the AM and PM peak hours. This is based on the 2035 No-Build HCM LOS E in the AM peak hour and LOS F in the PM peak hour. The model V/C is LOS F in the AM peak hour and LOS F in the PM peak hour.


Congestion Score: This segment experiences a combined congestion score of 8 in the AM peak period, indicating severe congestion from multiple causes, and 6 in the PM peak period, indicating moderate congestion problems.

Cause of Congestion

The high 2035 No-Build volumes on the mainline (7846 AM / 7934 PM), Lakewood Boulevard loop on-ramp (633 AM / 520 PM), Lakewood Boulevard diamond on-ramp (504 AM / 601 PM) and Bellflower Boulevard on-ramp (1281 AM / 758 PM) contribute to congestion.

A 5th general purpose lane is added westbound via the Downey Avenue on-ramp. Upstream of this added lane (where there are only 4 general purpose lanes) has considerable congestion due to restricted capacity of the mainline.

The high volumes on the mainline and on-ramps east of Downey Avenue are greater than the capacity of the freeway at this location. This causes congestion between Downey Avenue and I-605 where the four mainline general purpose lanes do not provide enough capacity.

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CONGESTION HOT SPOT WB-8

Location: Paramount Boulevard to Cherry Avenue Performance Measures

PeMS Speed Data: This segment experiences slow mainline speeds with current average speed of 35-45 mph during the AM peak period. During the PM peak period, speeds are greater than 55 mph, indicating that the congestion issue based on speed measurements occurs only during the AM peak period.

2035 No-Build Level of Service: The level of service analysis indicates extreme congestion during both the AM and PM peak hours. This is based on the 2035 No-Build HCM LOS F in the AM peak hour and LOS F in the PM peak hour. The model V/C is LOS E in the AM peak hour and LOS E in the PM peak hour.


Congestion Score: This segment experiences a combined congestion score of 7 in the AM peak period, indicating severe congestion from multiple causes, and 4 in the PM peak period, indicating limited congestion problems.

Cause of Congestion

The high 2035 No-Build volume on the mainline (8,876 AM / 8,471 PM) and the moderate volumes on Paramount Boulevard on-ramp (592 AM / 776 PM) and Cherry Avenue off-ramp (432 AM / 672 PM) contribute to the congestion at this location.

A short weaving distance of approximately 700 feet exists between the Paramount Boulevard on-ramp and the Cherry Avenue off-ramp. This creates an operational issue due to the very short weaving distance in combination with the large volume of vehicles on the mainline and moderate volumes on the on- and off-ramps.


Location: Atlantic Avenue Off-Ramp Diverge to N/S 710 Connector Ramp Diverge Performance Measures

PeMS Speed Data: This segment experiences extremely slow mainline speeds with current average speed of less than 35 mph during the AM peak and greater than 55 mph in the PM peak, indicating that the congestion issue is exclusively during the AM peak period.

2035 No-Build Level of Service: – The level of service analysis indicates congestion during both the AM and PM peak hours. This is based on the 2035 No-Build HCM LOS D

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in the AM peak hour and LOS D in the PM peak hour. The model V/C is LOS D in the AM peak hour and LOS E in the PM peak hour.


Congestion Score: This segment experiences a combined congestion score of 5 in the AM peak hour, indicating moderate congestion and 3 in the PM peak period, indicating limited congestion problems.

Cause of Congestion

The high 2035 No-Build volume on the mainline (9,590 AM / 9,397 PM), W 91 – N/S 710 connector off-ramp (3,741 AM / 3,640 PM) and Atlantic Avenue off-ramp (960 AM / 945 PM) are all nearing capacity and contribute to the congestion at this location.

The high volumes mentioned above on the mainline and on the two closely spaced successive off-ramps create a situation where the vehicles extensively utilize the outside lanes to “get ready” to exit. The two successive off-ramps are approximately 740 feet apart. This natural movement to the outer right lanes causes a significant operational deficiency that is not necessarily captured by HCM.


Location: N 710 – W 91 Connector Ramp/Atlantic Avenue On-Ramp Merge Performance Measures

PEMS Speed Data: The segment immediately upstream from this merge experiences extremely slow speeds with current average speed of less than 35 mph during the AM peak and greater than 55 mph in the PM peak, indicating that the congestion issue is exclusively during the AM peak period.

2035 No-Build Level of Service: The 2035 No-Build HCM LOS is F during the AM peak hour and LOS C in the PM peak hour for this merge junction.



Cause of Congestion

The high 2035 No-Build volume on the N 710 – W 91 Connector Ramp/Atlantic Avenue On-Ramp (1,446 AM / 1,307 PM) is above capacity for a one-lane ramp and the mainline has moderate volume (4,889 AM / 4,812 PM) at this location.

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The N 710 to W 91 connector loop on-ramp joins with the Atlantic Avenue WB on-ramp to create a two-lane on-ramp to WB 91. This two-lane ramp immediately drops to one lane as it joins the freeway (which has three general purpose lanes prior to the on-ramp merge). This lane drop is the primary cause of the LOS F at this merge junction.

As a result of the congestion described above, the westbound SR-91 typically backs up to the east at this location past WB-8 and WB-9.


Location: S 710 – W 91 Connector Ramp Merge to Long Beach Boulevard Performance Measures

PEMS Speed Data: This segment experiences extremely slow speeds with current average speed of less than 35 mph during the AM peak and greater than 55 mph in the PM peak, indicating that the congestion issue is exclusively during the AM peak period.

2035 No-Build Level of Service: The level of service analysis indicates significant congestion during both the AM and PM peak hours. This is based on the 2035 No-Build HCM LOS E in the AM peak hour and LOS D in the PM peak hour. The model V/C is LOS D in the AM peak hour and LOS E in the PM peak hour.



Cause of Congestion

The high 2035 No-Build volume on the mainline (9,432 AM / 7,616 PM) and the S 710 – W 91 connector on-ramp (3,366 AM, 1,844 PM) are approaching capacity. The Long Beach Boulevard off-ramp (332 AM / 440 PM) has moderate volumes at this location.

A short weaving distance of approximately 1,100’ between the S 710 – W 91 connector on-ramp and the off-ramp to Long Beach Boulevard creates an operational issue due to the large volume of vehicles using the connector and the mainline in the AM peak hour. A mainline lane drop occurs immediately west of the off-ramp to Long Beach Boulevard, which further exacerbates the operations in this area.

The relatively short distance between the Long Beach Blvd. ramps and the ramps serving Alameda St. and Santa Fe Avenue also contribute to congestion at WB-11.

The congestion resulting from WB-10 and WB-11 in the AM backs up the westbound freeway into WB-8 and WB-9 (or even further east on a frequent daily basis). Once past WB-11 (and alameda St./Santa Fe Interchange) westbound SR-91 generally appears to open up.

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7.3 SR-91 WESTBOUND CONGESTION HOT SPOT SOLUTION PROJECT DEFINITION

SUMMARY

The eleven congestion hot spot locations along SR-91 WB were further assessed and compared to determine how the congestion problem areas interrelate to one another. While some hot spots may stand alone in terms of their unique congestion and operational issues, others experience problems which are clearly related to upstream or downstream locations. The assessment of hot spot interconnectivity leads to a logical grouping of project definition segments that is then used to define a “hybrid” master plan of proposed freeway improvements that can provide the best investment for the maximum improvement benefit. In the case of SR-91 in the westbound direction, the eleven hot spot locations are combined into three logical “project definition” segments. The data and review of these segments show that they share operational issues and/or geometric issues. The three combined project definition segments for SR-91 westbound are as follows:

WB-1 – WB-4: Artesia Boulevard to W 91 - N/S 605 Connector Ramp Diverge

WB-5 – WB-7: S 605 – W 91 Connector Ramp Merge - Downey Avenue

WB-8 – WB-11: Paramount Boulevard to Long Beach Boulevard

CONGESTION SOLUTION PROJECT DEFINITION FOR SR-91 WB HOT SPOTS 91 WB-1 TO 91 WB-4

Location: Artesia Boulevard to W 91 - N/S 605 Connector Ramp Diverge Congestion Problem: This two mile segment is characterized by existing average speeds of less than 35 mph in the AM peak period and 45 to 55 mph in the PM peak period. Four local interchanges are spaced approximately ½ mile apart to the east of the SR-91/I-605 system interchange. Caltrans and FHWA standard for spacing between a system interchange and a local interchange is two miles and the standard spacing between local interchanges is one mile. The closely spaced interchanges do not meet Caltrans and FHWA Standards and contributes to mainline congestion as a result of merging and weaving of vehicles entering and exiting the freeway. Traffic volumes on westbound SR-91 begin to increase in the vicinity of the Artesia Boulevard entrance ramp, as more vehicles enter the freeway mainline than exit at the following Norwalk Blvd. interchange. This is also the location where vehicles begin to merge right to access mainline SR-91 WB mainline lanes 4 and 5 which exit on the N/S 605 connector. The two lane N/S 605 connector experiences congestion as the one lane NB 605 connector is over capacity. Congestion at this location results in queuing that backs up to the location where the N/S connector ramp diverges from the SR-91 mainline and also creates a long queue of congestion in mainline lanes 4 and 5 upstream of the N/S 605 connector ramp through the closely spaced local interchanges. The four localized hot spots result in a continuous, highly

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congested 2 mile segment of westbound SR-91. Future projected mainline freeway volumes will contribute to making congestion in this segment worse in the future too. Congestion Solution: To address the congestion problem the following improvements provide a measurable congestion improvement as summarized below:

Add 1 mainline lane from Artesia Boulevard to I-605 and widen N/S 605 connector ramp diverge from 2 lanes to 3 lanes.

Maintain existing auxiliary lanes from Bloomfield Avenue to Norwalk Boulevard; Norwalk Boulevard to Pioneer Boulevard; and Pioneer Boulevard to I-605 connector exit.

Remove existing Norwalk Boulevard to WB-91 direct on-ramp and convert to “D” ramp configuration. A “D” ramp configuration involves converting the existing uncontrolled, high speed movement onto the ramp to a signal-controlled, slow right-turn movement.

Remove existing Pioneer Boulevard to WB-91 direct on-ramp and convert to “D” ramp configuration.

Widen existing WB 91 Pioneer Boulevard and Artesia Boulevard exit ramps to provide 2-lane exits.

Congestion Improvement and Benefit/Cost Assessment: The improvement to congestion conditions and other key performance assessments relative to the cost for the improvements of the WB-1 to WB-4 reach include:

Preliminary Cost Range: $ 50 M - $ 60 M (assuming modification of the full 91/605 system interchange is not included and would be a separate project)

2035 Level of Service: The 2035 Build level of service analysis indicates reduced congestion. This is based on comparing the 2035 No-Build HCM, which is generally LOS E in the AM peak period and LOS E in the PM peak period for the mainline, to the 2035 Build HCM which is generally LOS D in the AM peak period and LOS D in the PM peak period. The 2035 mainline peak hour volumes that experience improved congestion conditions with the improvements are approximately 7,500 AM/9,000 PM in this reach.

Accidents: Existing accident history generally exceeds the statewide average by 30 percent or more in this reach, particularly at the N/S 605 connector, which is expected to decrease with the proposed improvements.

Environmental/Right of Way: Environmental considerations for this reach of improvements are anticipated to be of moderate significance. Right of way acquisition requirements are anticipated to be of low significance.

Congestion Score: This reach experiences a combined congestion score range of 2-3 in the AM peak period and 3-4 in the PM peak period for 2035 Build compared to 5-10 in the AM and 7-10 in the PM for 2035 No-Build indicating a high significance of reduced congestion.

Low/Moderate/High Qualitative Benefit/Cost Assessment: The assessment of 91 WB-1 to WB-4 is considered to be of high value based on the significance of the improvement

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benefit gained for the cost invested and the significant reduction in the future congestion.


Location: S 605 – W 91 Connector Ramp Merge – Downey Avenue Congestion Problem: This three mile segment is characterized by existing average speeds of less than 35 mph in the AM peak period and over 55 mph in the PM peak period. The lane drop from two to one lane on the S 605 – W 91 connector ramp, combined with the heavy volumes on this connector ramp, result in congestion at the merge with westbound SR-91. A short weaving distance of approximately 650’ between the Bellflower Boulevard on-ramp and the Clark Avenue off-ramp, combined with the large volumes using Bellflower Boulevard on-ramp and the mainline, result in congestion at this location. A general characteristic of this segment is a lack of capacity on the mainline. West of Downey Avenue the freeway has five general purpose lanes; however, there are only four general purpose lanes between Downey Avenue and I-605. This lack of capacity and other issues within this segment causes considerable congestion and backups in the westbound direction. The three localized hot spots result in a continuous highly congested 3 mile segment of westbound SR-91.

Congestion Solution: To address the congestion problem the following improvements provide a measurable congestion improvement as summarized below:

Reconstruct S 605 connector ramp to be two lanes as it merges onto WB SR-91. One of these lanes will be an additional general purpose lane extending to Downey Avenue (to join the existing 5th general purpose lane near Downey Avenue) and one lane will be for maintaining the existing auxiliary lane to Bellflower Boulevard.

Provide two-lane exit ramp to Bellflower Boulevard.

Eliminate the Clark Boulevard off-ramp.

Maintain existing auxiliary lane between Bellflower Boulevard on-ramp and Lakewood Boulevard off-ramp (connect auxiliary lane through the closed Clark Boulevard interchange).

Maintain existing auxiliary lane between Lakewood Boulevard on-ramp and Downey Avenue off-ramp.

Provide two-lane exit ramp to Downey Boulevard.


Preliminary Cost Range: $ 75 M - $ 85 M

2035 Level of Service: The 2035 Build level of service analysis indicates reduced congestion. This is based on comparing the 2035 No-Build HCM, which is generally LOS E

FEASIBILITY REPORT


in the AM peak period and LOS F in the PM peak period for the mainline, to the 2035 Build HCM which is generally LOS D in the AM peak period and LOS E in the PM peak period. The 2035 mainline peak hour volumes that experience improved congestion conditions with the improvements are approximately 7,500 AM/8,500 PM in this reach.

Accidents: Existing accident history generally does not exceed the statewide average by 30 percent or more in this reach, except at the S 605 connector ramp, which is expected to decrease with the proposed improvements.

Environmental/Right of Way: Environmental considerations for this reach of improvements are anticipated to be of moderate significance. Right of way acquisition requirements are anticipated to be of moderate significance (primarily related to Bellflower Blvd widening).

Congestion Score: This reach experiences a future combined congestion score range of 5-6 in the AM peak period and 3-5 in the PM peak period for 2035 Build compared to 7-9 in the AM and 5-6 in the PM for 2035 No-Build, indicating a high significance of reduced congestion.

Low/Moderate/High Qualitative Benefit/Cost Assessment: The assessment of 91 WB-5 to WB-7 is considered to be of moderate value based on the improvement benefit gained for the cost invested and that some congestion is only moderately improved.


Location: Paramount Boulevard – Long Beach Boulevard Congestion Problem: This two mile segment is characterized by existing average speeds of generally less than 35 mph in the AM peak period and over 55 mph in the PM peak period. The segment between Paramount Boulevard and Cherry Avenue has a short weaving distance of 700’. This creates an area of congestion due to the short weaving distance in combination with the large volumes on the mainline, Paramount Boulevard on-ramp and Cherry Avenue off-ramp. Approaching the I-710 interchange, there are two closely spaced successive off-ramps (one to Atlantic Avenue and the other to N/S 710) with very heavy volumes associated with each off-ramp and the mainline. This creates a situation where vehicles extensively use the outside lanes to “get ready” to exit. In the future, a third off-ramp will potentially be added in this area to access the S 710 Freight Corridor as part of the I-710 Corridor Project. Another cause of congestion is where the N 710 – W 91 connector/Atlantic Avenue on-ramp merges with the mainline. The heavy volumes associated with this on-ramp and the mainline and the reduction to a one-lane ramp create a merge junction that is operating at LOS F. Lastly, a short weaving distance of approximately 1,100’ between the S 710 – W 91 connector on-ramp and the Long Beach Boulevard off-ramp, in combination with the large volumes on the mainline and connector, causes congestion at this critical area. A mainline lane drop occurs immediately west of the off-ramp to Long Beach Boulevard, which further exacerbates the operations in the westbound direction (plus congestion related impacts associated with the ramps to Alameda St./Santa Fe Ave. west of Long Beach Blvd.). The four localized hot spots result in a continuous highly congested 2 mile segment of westbound SR-91.

FEASIBILITY REPORT


Congestion Solution: To address the congestion problem the following improvements provide a measurable congestion improvement as summarized below:

Braid Paramount Boulevard on-ramp and Cherry Avenue off-ramp.

Provide new auxiliary lane from Cherry Avenue on-ramp to Atlantic Avenue off-ramp.

Maintain existing auxiliary lane prior to N/S 710 off-ramp.

Add one general purpose lane from N/S 710 off-ramp (near Atlantic Avenue) to Santa Fe Avenue.

Provide two-lane exit to Long Beach Boulevard.

Relocate N 710 – W 91 connector ramp as shown for the I-710 Corridor Project.


Preliminary Cost Range: $ 160 M - $ 200 M

2035 Level of Service: The 2035 Build level of service analysis indicates some reduced congestion. This is based on comparing the 2035 No-Build HCM, which is generally LOS D-F in the AM peak period and LOS D-F in the PM peak period for the mainline, to the 2035 Build HCM which is generally LOS D-E in the AM peak period and LOS D-E in the PM peak period. The 2035 mainline peak hour volumes that experience improved congestion conditions with the improvements are approximately 9,000 AM/8,500 PM in this reach.

Accidents: Existing accident history does not exceed the statewide average by 30 percent or more in this reach.

Environmental/Right of Way: Environmental considerations for this reach of improvements are anticipated to be of moderate significance. Right of way acquisition requirements are anticipated to be of moderate significance.

Congestion Score: This reach experiences a combined congestion score range of 2-7 in the AM peak period and 1-4 in the PM peak period for 2035 Build compared to 5-7 in the AM and 3-5 in the PM for 2035 No-Build indicating a moderate significance of reduced congestion.

Low/Moderate/High Qualitative Benefit/Cost Assessment: The assessment of 91 WB-1 to WB-4 is considered to be of moderate value based on the significance of the improvement benefit gained for the cost invested and the moderate improvements in congestion scores.

Documents

FREEWAYS CONGESTION HOT SPOT PROBLEM & …media.metro.net/projects_studies/I605/605_07_part1.pdfLimits and logical terminus of the congestion problem area . An effectiveness analysis