Variable Speed Limit (VSL) systems enable freeway system managers to dynamically change the posted speed limit on a section of roadway in response to varying conditions. VSL system goals may include homogenizing traffic flow, improving safety, and/or reducing driver stress.Although it is understood that the effectiveness of VSL systems is impacted by the level of driver compliance, which itself is influenced by the extent of speed limit enforcement, very little is known about the strength of these impacts. This paper makes use of a simulation model to evaluate the sensitivity of the safety and operational impacts of VSL to driver compliance.Several scenarios for driver compliance were modeled using the PARAMICS microscopic traffic simulator. Findings indicated that VSL impacts are very sensitive to the level of driver compliance. Safety was shown to be positively correlated with the level of compliance and travel time was shown to be negatively correlated. However, it was also found the magnitude of the impact is strongly influenced by the VSL control strategy (i.e. set of rules for incrementing and decrementing the speed limits) being used. Therefore, selection of the VSL control strategy cannot be done independently of the decision regarding speed limit enforcement.

Automatic vehicle location (AVL) and automatic passenger counting (APC) systems can provide rich archived databases for analysis. Previous work has focused on using AVL–APC data to evaluate system performance using various quantitative performance measures and data visualization methods. Given the large volume of data, there is a benefit to automating the creation of performance measures and data visualizations and “pushing” interesting information to users, rather than requiring users to create the performance measures and figures and sift through them on their own. This paper presents a methodology for identifying bus stops that are not meeting performance standards for schedule adherence and the factors that cause inadequate performance. The methodology is designed to be automated and therefore can be applied efficiently to AVL–APC data for an entire transit network. Use of this proposed method will enable transit agencies to identify service quality issues and their root causes more efficiently.

Transit "pass-through" lanes provide transit vehicle priority at freeway interchanges. "Pass-through" lanes allow a transit vehicle to exit the freeway at an interchange, cross straight through the intersecting arterial road, and re-enter the freeway. This treatment allows transit vehicles to bypass congestion on the mainline between the beginning of the off-ramp and the end of the on-ramp. This paper outlines a methodology to evaluate if transit "pass-through" lanes are economically justified at a given interchange and provides a method for prioritizing candidate locations. The methodology provides an objective and consistent decision making method, reduces the effort required for practitioners to assess the need for "pass-through" treatment at a given interchange, and helps ensure that limited resources are directed towards interchanges that are expected to experience the greatest benefit per dollar spent.The proposed methodology is based on an analytical approach that compares the value of travel time savings (for passengers and transit vehicles) with the construction and maintenance costs of the transit "pass-through" lane treatment.