2005 Report Relevant to MP2035 Discussion: Does Light Rail Worsen Congestion and Air Quality?

The linked article discusses the “counterintuitive” prospect of decreasing VMT while increasing congestion and pollution.  It might provide a useful basis for discussion of MP2035.

Congestion:

The reduction of VMT is normally expected to reduce delays for the remaining motor vehicles. However, since the roadway capacity is reduced by two lanes, the smaller VMT might be offset. The MAG model’s projected vehicle-hours of travel (VHT) indicate that the loss of capacity is a larger factor than the diversion of drivers from their cars. For the region, the addition of light rail is expected to increase VHT by 0.45 percent. For the corridor served by light rail, VHT are expected to increase by 1.23 percent. So even though fewer miles would be traveled, those trips would take longer if light rail is added to the traffic mix.

Pollution:

Inasmuch as light-rail transit is often promoted as a means of improving air quality, the indication that it will actually increase pollution may strike many as counterintuitive. After all, aren’t we luring some people out of their cars? Don’t fewer cars mean less pollution? So far as it goes, the answer is yes. However, by placing the train tracks in the street, we reduce roadway capacity. The reduction in capacity more than offsets the reduction in numbers of vehicles using the roadway. The remaining vehicles take longer to travel through the narrower roadway. This leads to more fuel consumed and higher pollution.

While this article discusses the loss of vehicle lanes to light rail, MP2035 is focused on removing lanes for bikes and buses – each with far less carrying capacity than light rail.  One can only imagine the congestion/air quality concerns would be amplified when lanes are replaced with low-passenger-count alternatives.