Baton Rouge area motorists may be surprised to know that the speed limit is 75 mph on a nearly 200-mile stretch of Interstate 49 generally between Opelousas and Shreveport.

The new speed limit, the highest in Louisiana, stems from a 2010 bill.

That measure, Senate Bill 616, authorized the state Department of Transportation and Development to raise the maximum legal speed when engineering and traffic investigations showed it could be done safely.

“I was delighted that they did it for I-49,” said Senate Transportation Committee Chairman Joe McPherson, D-Woodworth and sponsor of the bill.

McPherson is familiar with the route affected because much of it is between his home and the State Capitol.

“Anyone who traveled I-49 knew that the traffic was driving on average higher than 70 mph,” he said.

DOTD officials said their studies showed that 85 percent of drivers along the route were traveling at or below 75 mph.

Setting the speed limit at the 85th percentile, they said, can help reduce crashes and move traffic efficiently.

“That is what a prudent driver feels comfortable and safe driving,” McPherson said.

“If you set your speed limit below that, it is kind of artificial,” he said.

DOTD officials said setting the speed limit too low — in this case at 70 mph — makes enforcement difficult and is often ignored by motorists.

The higher speed limit took effect in late April.

However, press releases spelling out the change were sent to the most affected parishes — St. Landry, Avoyelles, Evangeline, Rapides, Natchitoches and DeSoto parishes.

“I don’t think we have gotten any negative feedback,” said Jodi Conachen, communications director for DOTD.

“The trucking community has been very supportive,” she said.

Traffic volume on rural parts of I-49, which generally de-

scribes the area affected, is noticeably lighter than I-10.

Conachen said there are no plans to raise the speed limit elsewhere.

The higher speed limit marks a turnaround since 2007.

A report issued then by DOTD said it would be a bad idea to raise the speed limit to 75 mph on some interstate highways.

Legislative backers said at the time that the higher limit made sense on rural sections of interstate roads.

Raising speed limits was rare last year, according to the National Conference of State Legislatures in Denver.

The group cited action in Louisiana and Virginia, which raised its speed limit on rural and urban highways from 65 mph to 70 mph.