Details:

Creators:
Edara, Praveen K. ; Sun, Carlos ; Hou, Yi
Edara, Praveen K. ; Sun, Carlos ; Hou, Yi Less -
Corporate Creators:
University of Missouri--Columbia
Corporate Contributors:
United States. Federal Highway Administration
Subject/TRT Terms:
[+]
Algorithms Compliance Speed Limits Variable Message Signs Work Zone Safety Work Zone Traffic Control
Publication/ Report Number:
InTrans Project 06-277
Resource Type:
Tech Report
Geographical Coverage:
United States
Corporate Publisher:
Iowa. Dept. of Transportation
NTL Classification:
NTL-SAFETY AND SECURITY-Highway Safety;NTL-SAFETY AND SECURITY-Speed Limits;NTL-OPERATIONS AND TRAFFIC CONTROLS-Traffic Control Devices;
Abstract:
Variable advisory speed limit (VASL) systems could be effective at both urban and rural work zones, at both uncongested and congested sites. At uncongested urban work zones, the average speeds with VASL were lower than without VASL. But the standard deviation of speeds with VASL was higher. The increase in standard deviation may be due to the advisory nature of VASL. The speed limit compliance with VASL was about eight times greater than without VASL. At the congested sites, the VASL were effective in making drivers slow down gradually as they approached the work zone, reducing any sudden changes in speeds. Mobility-wise the use of VASL resulted in a decrease in average queue length, throughput, number of stops, and an increase in travel time. Several surrogate safety measures also demonstrated the benefits of VASL in congested work zones. VASL deployments in rural work zones resulted in reductions in mean speed, speed variance, and 85th percentile speeds downstream of the VASL sign. The study makes the following recommendations based on the case studies investigated: 1. The use of VASL is recommended for uncongested work zones to achieve better speed compliance and lower speeds. Greater enforcement of regulatory speed limits could help to decrease the standard deviation in speeds. 2. The use of VASL to complement the static speed limits in rural work zones is beneficial even if the VASL is only used to display the static speed limits. It leads to safer traffic conditions by encouraging traffic to slow down gradually and by reminding traffic of the reduced speed limit. A well-designed VASL algorithm, like the P5 algorithm developed in this study, can significantly improve the mobility and safety conditions in congested work zones. The use of simulation is recommended for optimizing the VASL algorithms before field deployment.
Format:
PDF
Funding:
TPF-5(081)
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:7d6c3dba93f24875f73d0c3e16aee20a6c520521c6523dbfc977e6a9b510ff89
Download URL:
https://rosap.ntl.bts.gov/view/dot/26306/dot_26306_DS1.pdf
File Type:

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