LOS ANGELES — The Reason Foundation last week released its 17th Annual Report on the Performance of State Highway Systems.

The study, by University of North Carolina Transportation Professor David Hartgen, measures the condition of all state-owned roads and highways from 1984 to 2006.

It also calculates the performance of each state in 12 categories, including pavement and bridge condition, traffic fatalities, congestion, and highway maintenance and administrative costs.

The study found that North Dakota is most effective in maintaining its roads and bridges, while New Jersey has the worst-performing, least cost-effective highway system in the nation.

Massachusetts’ roads were found to be the safest; Montana’s were found to be the deadliest.

Throughout the country, 24.1 percent of bridges are deficient or functionally obsolete, the study says. In Rhode Island, over 53 percent of bridges are deficient.

With regard to traffic, the study found that California fares worst, with an 83-percent congestion rate. Other states’ highways, however, are becoming increasingly jammed: Officials in 18 states reported that at least half of their urban interstates suffer from gridlock.

The Reason Foundation is a nonprofit organization that develops and promotes libertarian principles, including individual liberty and free markets. To download the study, click here.