Providing an efficient alternative to commuters traveling streets and freeways during rush hours, express bus services can relieve congested roadways and commuters as well, of the effects of extended, low speed, inefficient use of automobiles. The majority of autos removed from roadways by alternative express bus services are those driven by single occupants of the vehicles. Few other transportation modes or services provide such a demonstrably high percentage of riders opportunities to curtail rush hour driving as do express bus services. As the most significant measure of pollution and environmental impact on urban settings, vehicle trips, and specifically, rush hour trips by single occupant vehicles, would be most efficiently removed from congested streets and freeways by express buses. However, little evidence of the ability for express bus services to remove significant numbers of vehicles from streets and highways has been compiled or documented. While environmental factors and improvements are often presented as primary justification and incentives supporting express bus service implementation, follow-up studies and measures of these impacts tend to be vague, and are often ignored or curtailed, should they not support original projected effects on traffic congestion, travel times and other promised impacts of express bus services.
Reduction of auto commuting provided by express buses is most sustainable and effective when services bridge distances between central city work places and suburban residential locations with a degree of efficiency, economy and reliability that offers an attractive alternative to automobile commuting. Some studies and transportation officials have made a case for commuting alternatives by promoting employer subsidizing of bus and transit tickets; citing positive effects on the extended workday.
Express bus vehicles tend to be larger and longer than other buses in municipal fleets, and therefore should be expected to have commensurately greater effects and impacts on traffic, sidewalk and pedestrian settings, adjacent and nearby residential neighborhoods, schools and other public buildings, as well as, the pavement and roadbeds over which they pass. Bus routes that avoid or bypass the most congested and degraded of urban areas can reduce the impacts of their operation on environments they traverse.