Transportation Operations Group Designing for Speed, Congestion, and Delay in the Work Zone Gerald Ullman Research Engineer Texas Transportation Institute

Transportation Operations Group

Designing for Speed, Congestion, and Delay in the

Work ZoneGerald Ullman

Research Engineer

Texas Transportation Institute


Work Zone Safety Trends

600

800

1000

1200

1400

1996 1997 1998 1999 2000 2001 2002 2003

Work

Zone F

ata

liti

es

Per

Year

No WZ Influence

71%

During WZ Setup/

Removal4%

WZ Indirectly Involved

19%

WZ Conditions Directly Involved

6%


Work Zone Consequences 40,000 injuries/year nationally 120 workers killed annually $4.5 billion/year national economic

cost


Some other facts… 43,500 miles of the National Highway

System sees at least one day of work zone activity annually

• In summer, we lose the equivalent of 41 million vehicles per day of roadway capacity due to work zones


Work Zone Exposure

6.2

5.0

12.4

60.8

0 10 20 30 40 50 60 70

Active WorkZones

Inactive WorkZones

Vehicle-Miles-Traveled, Billions

With Closures Total


The Result…


Speed Management in Work Zones

Enforcement Speed control technologies


Enforcement considerations Realistic and

“reasonable” speed limits

Adequate coordination between DOT and enforcement agencies

Labor availability


Enforcement Circulating 2-3 mph

Stationary 3-13 mph Police Traffic Controllers 2-14 mph Operation Hardhat ???


Work Zone Speed Control Technologies

Enforcement surrogates Driver information/feedback Perceptual methods


Enforcement Surrogates “Dummy” vehicles ----- Unmanned radar 0-2 mph Remote enforcement ----- Automated enforcement -----


Driver Information/Feedback Changeable Message

Signs (CMS) 0-2 mph CMS w/ radar 0-6 mph Speed trailers 2-10 mph CB Wizard 0-2 mph Variable Speed Limits 0-5 mph*


Perceptual Methods Rumble strips 1-6 mph Transverse markings 0 mph Narrowed lanes 0-8 mph


Congestion and Delay Management in Work Zones

Increase work zone capacity and efficiency of flow

Reduce traffic demands at work zone bottleneck points

Communicate accurate estimates of delay and congestion expectations


“Get In, Get Out, Stay Out”

77% motorists prefer long-term repairs, even if delays are more significant

Focus on longer-lasting materials, better construction methods, longer service life horizon

Major constraint: $$


Increasing Capacity

Late-merge or dynamic merge control

Moveable barrier systems Contractor accountability


Late Merge


Moveable barrier


Contractor Accountability Arizona SR 68 (FHWA-HOP-04-032) $400k incentive pool Travel times exceeding 27 minutes

reduced incentive pool


Reducing Traffic Demands

Working at night and weekends Full roadway closures Portable Intelligent Transportation

System (ITS) technology


Extent of Nightwork

0%

20%

40%

60%

80%

100%

Midn

ight

2:00

AM

3:00

AM

6:00

AM

8:00

AM

10:00

AM

Noon

2:00

PM

4:00

PM

6:00

PM

8:00

PM

10:00

PM

Per

cen

t o

f C

on

trac

t W

ork

Zo

nes

Wit

h A

ctiv

e L

ane

Clo

sure

s A

t T

hat

Tim

e o

f D

ay

Night work 18+ Hours/day Daytime


Concerns about Nightwork

Efficiency, quality of work Safety

Traveling public Workers

Worker quality of life


Full Roadway Closures Roadway completely closed, traffic

routed to alternative routes Increases work efficiency Eliminates traffic/work crew conflicts Requires high degree of coordination

and contingency planning Impacts off-site difficult to predict

and assess


A Broader Perspective


ITS Applications in Work Zones


Key principles

Motorists should not be told something they already know

Motorists should never be provided incorrect information (must maintain credibility)

Motorist diversion thresholds: 10-20 minutes delay


Questions

Documents

Transportation Operations Group Designing for Speed, Congestion, and Delay in the Work Zone Gerald Ullman Research Engineer Texas Transportation Institute