Planning for highways has never been an exact science, but dramatically higher gasoline prices have made it an even dicier proposition.

The future of transportation in the United States and particularly the future of private automobile usage raise questions that are hanging over the nation’s highway planners.

Michael Johnston, president and CEO of the Kansas Turnpike Authority, was in Lawrence this week to celebrate the start of the largest KTA construction project ever, the construction of two new bridges over the Kansas River and other improvements near Lawrence. Although each bridge will be designed to carry up to four lanes of traffic, Johnston said the KTA isn’t even starting to look at plans to widen its toll road beyond the current four lanes between Lawrence and the turnpike’s eastern end.

The uncertainty of future highway usage is just too hard to predict – but current indicators aren’t strong. Turnpike usage by K-Tag travelers – mostly Kansans, many of whom commute to work – has risen slightly in 2008, Johnston said. But usage by travelers, mostly from out of state, of the turnpike for longer trips is down by about 5 percent. The result is a overall decline of about 2.5 percent in turnpike usage.

Whether that trend will continue is uncertain, and it’s that uncertainty that is making some officials hesitant to undertake large, long-range projects to accommodate car and truck traffic.

It may have an impact, for instance, on whether the Kansas Legislature considers a new highway plan after the current funding package runs out this year. Highway projects have always been a high priority and a popular way for both state and national legislators to “bring home the bacon” for their constituents. But tight budgets and the uncertainty about future needs are likely to make many lawmakers, including Kansas legislators, hesitant to commit large sums of taxpayer money to highway expansion and improvements.

Is America’s long love affair with the automobile coming to an end? Until that question is answered, plans for major new highway projects are likely to remain on hold.