Over the past 20 years the direct costs of traffic congestion grew more than 400% to an estimated $78 billion in 2005. These costs consist of the time lost to drivers because of the increase in average commute time that is caused by excess traffic, combined with the
excess fuel consumption attributable to such congestion. (The total cost of traffic congestion is much higher and also includes the cost of higher accident rates, congestion-related stress, missed meetings, lost productivity, shipping delays and related business inefficiencies.) At this rate, and assuming stable gasoline prices, congestion costs will grow to $240 billion by 2020, an average of $1,700 per highway commuter per year.
It is not your imagination: traffic congestion is bad and getting worse in almost all major metropolitan areas. From the 1950’s into the 80’s, pockets of congestion would appear but relief would follow within a few years in the form of highway expansion. Beginning in the 1980’s highway expansion began to decline, resulting in a relentless increase in congested traffic. This trend is likely to get worse. Designing an optimal solution requires a clear understanding of the role private vehicle travel plays in our economy.