A dynamic late lane merge system reduced vehicle emissions by 15.7 percent at a highway work zone in southern Michigan.

Case study of wok zone ITS applications in Kalamazoo, Michigan

Date Posted
12/17/2013
Identifier
2013-B00886
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Evaluation of the Dynamic Late Lane Merge System at Freeway Construction Work Zones: Final Report

Summary Information

This study evaluated the effectiveness of a dynamic late lane merge system (DLLMS) installed at work zones on I-94 during the 2006 construction season in southern Michigan. The system used microwave traffic sensors, wireless communications, and a series of portable dynamic message signs (DMS) to direct drivers when to merge. When congestion was detected in the open lane (lane without the tapered closure) and average traffic speeds dropped below a preset threshold level of 35 mi/hr, dynamic message signs upstream were activated to advise drivers to “Use Both Lanes to the Merge Point” to preempt queuing and improve traffic flow.

METHODOLOGY

Evaluators compared freeway performance data collected at the DLLMS site with data collected at the control site equipped with only traditional work zone controls. Fuel consumption and emissions benefits were modeled based on flow, delay, number of stops, and travel speed data are as observed in the field.

FINDINGS

The table below compares performance between the control site and test site resulting fuel consumption benefit of using DLLMS during the 11 week test period.

Description
EB I-94
WB I-94
Length of advance warning area (ft)
21,120
20,064
Average hourly volume (veh/hr)
990
1,207
Number of weekdays DLLMS was operational
55
55
Number of hours in peak period
2
2
Total travel in vehicle miles
435,600
504,526
Average delay (sec/veh/10,000 ft)
181.11
67.67
Total delay in vehicle hours
5,479
2,496
Average number of stops per vehicle
4
2
Total stops per hour
3,960
2,414
Average operating speed (mi/hr)
29.5
47.6
Total fuel consumption (gallons)
21,796
18,384
Total fuel savings for the work zone during the worse period (gallons)
3,412

The table below compares the vehicle emissions for the EB I-94 control site and the WB I-94 test site during a congested PM peak period. There was a 15.7 percent reduction in the amount of pollutants produced by vehicle emissions for WB I-94 with the installation of the
DLLMS.

Description
Control Site
EB I-94
Test Site
WB I-94
Carbon Monoxide Emissions (grams)
1,523,540
1,285,042
Nitrogen Oxide Emissions (grams)
296,426
250,022
Volatile Oxygen Emissions (grams)
353,095
297,821
Total Emissions (grams)
2,173,061
1,832,885
Percent Reduction in Total Vehicle Emissions
per congested PM peak period
15.7%
Deployment Locations