North Dakota does the best job maintaining its roads and bridges and New Jersey has the worst-performing, least cost-effective highway system in the nation, according to an annual Reason Foundation study that measures each state’s road conditions and expenditures. The Reason Foundation’s 17th Annual Report on the Performance of State Highway Systems measures the condition of all state-owned roads and highways from 1984 to 2006. The study calculates the effectiveness and performance of each state in 12 categories, including pavement condition, bridge condition, traffic fatalities, congestion, highway maintenance costs, and administrative costs.

According to the study, Massachusetts’ roads are the safest and Montana’s are the deadliest. Across the country, 24.1 percent of bridges are deficient or functionally obsolete. In Rhode Island, however, more than 53 percent of bridges are deficient. California has the most traffic congestion: 83 percent of its urban interstates are congested. But other states are becoming increasingly gridlocked: 18 states report at least half of their urban interstates are jammed. Even South Dakota has traffic congestion now.

The Reason Foundation’s full study is available online at State-by-state rankings are available at, and deficient bridges rankings are available at