Cross-cutting Issues

Weigh-in-motion (WIM) systems have been in use for several years, and the technology and accuracy have steadily improved. This paper describes the design, testing, and implementation of the first five Illinois State Toll Highway Authority (Tollway) WIM stations. Tollway applications employ a special configuration for enforcement by the Illinois State Police (ISP) in a way not typically implemented elsewhere, instantaneously identifying the type of apparent violation and displaying that to an ISP vehicle. WIM has proved to be valuable as an enforcement and engineering tool, since detailed vehicle statistics are automatically generated. The technology is important in helping limit damage that overweight trucks do to core infrastructure. The first few WIM stations have payback periods of one to two years, hence the agency expects to deploy about another seven WIM stations in the next few years. The paper addresses performance, adjustments needed, typical reports, and “lessons learned.” The need for proactive maintenance to assure a high level of performance in particular is highlighted.

Authors: John Benda, Jim Powell, Bill Hereth

Presented at the 18th World Congress on ITS, October 2011, Orlando, Florida

The primary objective of this paper is to study and analyze the temporal characteristics of

traffic congestions and the associated speed distributions for congested expressways based on

the Floating Car Data (FCD) in Beijing. First, the temporal distributions of congestions with

different intensities are analyzed using the FCD of 5 workdays for a particular expressway

Link N26376. Results show that the longer the continuous congestion lasts, the lower the

speed distribution interval is. Then, the distribution curve is fitted, which finds that the

Log-Logistic model can well describe the survival function distribution of the severe

congestion durations for morning peak-hours of Tuesday. By comparison, it is found that the

duration distribution value of severe congestions at the aggregation interval of 2-minute is

lower than that at the 5-minute interval, and the duration distribution value of severe

congestions on Link N26376 is higher than that on its downstream Links N24162 and N23971.

Finally, the speed distributions in two proposed categories of congestion periods are analyzed

and compared. Results show that if the speed in the present time period falls in a higher

distribution interval, then the probability that the severe congestion will dissipate in the next

time period will be higher.

School of Traffic and Transportation, Beijing Jiaotong University

Texas Southern University

Beijing Transportation Research Center

Presented at the 18th World Congress on ITS, October 2011, Orlando, Florida