Guide to Calculating Mobility Management Benefits Victoria Transport Policy Institute
Special Considerations Various factors to consider when evaluating mobility management are discussed below.
Overlap There may be some degree of overlap among mobility management benefits. For example, congestion reduction can help reduce air pollution and increase economic productivity. Double-counting should be avoided to prevent exaggerating total benefits. Impacts should only be counted once if they are quantified and summed.
When calculating net benefits it is important to recognize the difference between net benefits and costs (changes in total resources) and economic transfers (shifts in resources). For example, road and parking fees are costs from users’ andbenefits (revenue) to businesses or government. Net costs are any incremental resources (staff and user time, money) devoted to collecting and enforcing payments.
Mobility Versus Efficiency Benefits Mobility management strategies can provide both mobility and efficiency benefits (Litman 2005). Mobility benefits result when improved transport options allow disadvantaged people to travel more, for example, if pedestrian and transit improvements allow non-drivers better access to education and employment. Efficiency benefits result when incentives cause travelers to shift to a more efficient mode, for example, if HOV priority causes commuters to shift from driving alone to ridesharing or using public transit. Both types of benefits should be considered when evaluating mobility management. This can be confusing, because they are measured in different ways: mobility benefits are indicated by increased personal travel by disadvantaged people, while efficiency benefits are indicated by reductions in total motor vehicle travel.
Analysis Scope The temporal (time) and geographic scope of analysis can significantly affect economic evaluation results. Transportation planning decisions can have durable and indirect impacts, so a broad scope, sometimes called sustainability planning, is usually justified. For example, a particular transportation planning decision can affect the quality of travel options (walking, cycling, driving, public transit, etc.), regional land use development patterns, energy consumption and pollution emissions, causing dispersed economic and ecological impacts.
Expanding the analysis scope often affects results. In particular, urban highway capacity expansion tends to provide larger short term benefits which decline over time due to induced travel (“Rebound Effects,” VTPI, 2006), while transit and HOV priority projects tend to have smaller short-term benefits that increase over time. Similarly, land use reforms usually require decades to achieve their full benefits. As a result, a narrower scope tends to favor automobile-oriented improvements while a broader scope tends to favor mobility management solutions.