Missoula Measures - Car Trips
The goal of an effective transportation system is to move people (including the elderly, children, and people without motor vehicles) around as efficiently, safely, and quickly as possible. We also want to do this in a way we can afford and that does not severely impact the environment and quality of life. There are many competing goals in such a system. The average Missoulian wants to hop in the car and quickly get anywhere, to drive without getting stuck in traffic, to find free parking easily, to reduce air pollution, to maintain the quality of our neighborhoods and downtown, and to have options to the car that are extremely easy to use. Progress on one front often leads to deterioration or unwanted change on another front. As Missoula has grown from a small town to bustling mid-sized western city, we are facing more and different kinds of challenges. The one constant seems to be our continuing love affair with our cars.
Vehicle miles traveled (VMT) is only one gauge of our progress and our challenges in transportation. It is a placeholder until we find measures that better reflect several facets of our transportation issues, including the number of vehicle trips, the number of people in each vehicle, the distance of trips, and the impact of being a regional center.
Nationally, VMT has been increasing as much as four times as fast as population growth. Missoula is not bucking this trend. Our recent modeling reflects a population increase of 23% by the year 2015 (to 106,150), and projections are for the vehicle miles traveled to increase by 47%. All estimates have us driving more and further, especially to the degree that we sprawl. One confounding factor is that it is hard to gauge VMT traveled by locals as opposed to out-of-town tourists and shoppers — who, for instance, account for 30% of the traffic on Reserve and Brooks. And meanwhile, we all live in a limited air shed that is already impacted seriously by transportation-related pollution.
2010 Missoula Urban Transportation Plan, Missoula Office of Planning & Grants
Americans average 9.7 trips per day per household. (ITE Trip Generation Manual) The Missoula number is slightly lower, about 8.5 trips per day. (Campbell) Nationally, the percentage of total car trips that involve getting to work has been declining over the past 20 years, from 35% to 28%. The percentage of family and personal business trips and social and recreational trips have been increasing. (U.S. Person Trips by Private Vehicles, Transportation Air Quality: Selected Facts & Figures, U.S. DOT)
The VMT numbers are calculated from the Missoula Study Area, which stretches from the top of Grant Creek to south of Lolo, and from west of the Wye to Bonner. Of the 1,358,836 miles estimated to be driven in 1994, the number drive on I-90 was 270,000. The great majority of the miles — over 622,000 — were driven on primary arterials such as Reserve and Brooks. (1996 Missoula Transportation Plan Update) In 1994, Missoula’s VMT averaged 17.3 miles per day per capita.