Sustainability

Halting climate change will require a concerted effort to reduce emissions from on-road vehicles. While significant progress has been made to improve vehicle efficiency and reduce CO 2 emissions, surface transportation accounted for half the increase in US green-house gas (GHG) emissions over the past two decades. Today, surface transportation accounts for 24 percent of all US emissions. Automobile improvements alone will not be sufficient to meet federal and state emissions targets; policy makers also need to identify solutions that reduce the demand for car travel. Information technology...

In metropolitan areas, public transportation has been encouraged as a sustainable mode because they can effectively transport many people and have less impact on traffic congestion and environment. In order to increase public transportation ridership, many jurisdictions have attempted to provide improved travel time and reliability of the public transportation system. These efforts include installing transit signal priority, dedicated median/curb bus lanes, bus rapid transit, bus bypass shoulder lanes, et cetera. In Korea, dedicated median bus lanes have been installed and operated since...

The traditional methodology for estimating vehicle emissions based on vehicle miles traveled and average speed is not reliable because it does not consider the effects of congestion, control devices, and driving mode (cruise, acceleration, deceleration, and idle). The authors developed an analytical model to predict vehicle activity on signalized arterials with emphasis on oversaturated traffic conditions. The model depends only on loop detector data and signal settings as inputs and provides estimates of the time spent in each driving mode, which consequently leads to more accurate...

Traditionally, the amount of air pollutant emissions from motor vehicles—hydrocarbons, carbon monoxide, and oxides of nitrogen—is estimated from emission factors based on trip and vehicle miles traveled and aggregate measures of vehicle activity (e.g., average vehicle speed). This method is not reliable for urban networks, as it does not consider the effect of traffic signals and congestion. There is a need to predict vehicle activity by mode of operation, i.e., time spent in cruise, acceleration, deceleration, and idle to obtain improved emission estimates. An analytical model for...