A new study of road conditions in the U.S. says California leads the country in roads in poor shape.

Transportation California, a Sacramento-based coalition of contractors, unions and other organizations, and The Road Information Program, a Washington, D.C.-based nonprofit organization that researches, evaluates and distributes economic and technical data on highway issues, released a study this week that ranks California’s roads dead last out ofl 50 states in terms of roadway quality and per capita dollars being spent to improve them.

Last year the state's roads were third worst in the nation, the groups said. Now, with 37% of state’s 168,000 miles of roads were rated “poor,” California has fallen to dead last on the list. Other states in the bottom five were Louisiana at 27%, Massachusetts at 25%, and New Jersey and Missouri tied at 21%.

“A generation of under-investment in California's streets, highways, overpasses and bridges has resulted in a shameful deterioration of what once was a showcase transportation network,” said Larry Fisher, executive director of Transportation California.

The study found that travel in California increased 97% between 1980 and 2000 and its population increased 42% in the same period. Yet California invested less per person in transportation than any state over that timeframe.

The study revealed that California motorists collectively pay $12 billion, or $558 individually, in extra vehicle operating costs annually as a result of driving on roads in poor, mediocre and fair condition. Reducing the percentage of poor and mediocre roads to 20%, respectively, would save the average motorist $215 annually, and all California drivers $4.7 billion.

"Failing to increase our investment in transportation will only cost us more in the long run," Fisher said. Reconstruction costs four to five times more than repair and maintenance. The study notes that mediocre roads deteriorate faster than good roads and that more than a third of the state's roads are now in mediocre shape.