A set of methods that seamlessly measure and balance the performance and quality of service offered by all surface transportation modes.
The Highway Capacity Manual’s (HCM) auto intersection LOS method has served as the foundation for transportation impact analysis for decades. In recent years, it has become obvious that while these methods are reliable and effective for automobile planning and engineering purposes, they have become an obstacle to those who desire a more balanced approach to transportation planning--a system that gives equal weight to all modes of travel.
This is particularly true in the case of environmental impact analysis. The methods and thresholds used to determine when a proposeddevelopment would have a significant impact on the environment are auto-biased and serve to place auto circulation improvements as a higher priority than non-auto improvements. Furthermore, since auto circulation improvementsoften come at the expense of other modes, most jurisdictions that use the HCM's auto intersection LOS methods implicitly place priority on reducing aproject’s contribution to automobile congestion, often at the expense oftransit, bicycle, and pedestrian projects.
Methods that measure user perceptions of the transportation system and its performance.
Jurisdictions across the U.S. have gravitated towards using the Highway Capacity Manual’s (HCM’s) LOS measure as both their calculationmethod and their scale for determining significance thresholds. The HCM’s descriptions of its LOS letter grades (“A” through “F”) provide value judgments of these categories (e.g., “Acceptable”, “Tolerable”, and “Significant”) and imply they were developed based on users’ perceptions. It appears to be both an impact measure and significance threshold in one package, removing the subjectivity from identifying a significant impact. However, a review of the existing literature found little evidence to supports these links (see Flannery, et al., 2004).
More recent research has developed a multimodal level of service method for the 2010 edition of the HCM. This method (called the Urban Streets method) has made substantial progress towards linking LOS grades with user perceptions, butfound that perceptions did not always correlate well with standard LOS grades. More recent research by Flannery (2010) used user perception surveys to associate pedestrian LOS grades withperceptions, but this research will not be included in the methods contained in the 2010 HCM.
Multimodal LOS measures that correlate to safety and non-motorized mode choice outcomes.
Safety: Research by Sanders (2010) found no correlations beyond previously identified major contributors to pedestrian safety (e.g., the presence of sidewalks, number of traffic lanes, and traffic speed) and 2010 HCM Urban Streets multimodal LOS results.
Pedestrian and bicycling activities (non-auto street uses): Sanders (2010) is currently working to correlate safety elements such as street trees, landscaping, and public benches with pedestrian and bicycling demand along streets.
CFA is currently developing a series of groundbreaking research and product delopment projects designed to have quick payoffs for the practice of multimodal LOS measurement. The broad outlines of these research inititatives are:
Analyst-Defined Modal Comparisions
CFA is currently designing a software tool that will allow analysts to define, value, "weight" and communicate the performance tradeoffs between surface transportation modes.
New Methods for Multimodal LOS Measurement Based on User Perceptions
Building on the substantial work done in the field of multimodal LOS to-date, CFA is undertaking research to develop multimodal LOS methods that accurately reflect user perceptions. This research may require a partial or even complete redefinition of the traditional LOS grade system ("A" through "F") to be consistent with the perceptions of travelers.
Travel Forecasting Methods Based on Multimodal LOS
Theoretically, the LOS for biyclcing, walking, riding transit, or driving on a street should play a signficant role determining mode choice and trip generation. CFA is currently defining a suite of forecasting tools that will "pivot" off of the multimodal LOS methods, allowing LOS measures to serve as inputs to determine mode choice, route choice and trip generation forecasts.