[06/19/02]Travelers along four miles of U.S. 61 immediately north of Interstate 20 are likely to see traffic slow in that area as congestion increases, a Mississippi Department of Transportation official said.

The area has seen rapid growth in the past three years with addition of a school complex at Sherman Avenue and River Region Medical Center, but no substantial design or flow changes have been undertaken to handle the load.

MDOT assistant state traffic engineer John Smith said development can be “squirrelly” until a kind of traffic equilibrium is reached as areas like U.S. 61 North grow. He said increasing congestion typically decreases drivers’ speeds but lowering the speed limit without strictly enforcing it does not.

Drivers going north from where U.S. 61, the town’s main north-south highway, splits with Interstate 20 face a speed limit of 45 mph for nine-tenths of a mile, to a point between the RiverHills Bank branch and Super Jr. From there to a quarter-mile north of Bowie Road, 1.75 miles, the road’s speed limit is 55 mph except for a three-tenths-of-a-mile 45-mph zone centered at Sherman Avenue, which leads to Sherman Avenue Elementary School on the west and River Region on the east. Just past Bowie Road, the limit increases to 65 mph.

About 24,000 vehicles a day travel the highway from I-20 to Bowie Road, according to the latest available MDOT average daily traffic count figures, from 2000. The hospital and anticipated accompanying growth was expected to add as much as several thousand vehicles a day to that number.

The four-lane, divided stretch of highway from I-20 to the hospital entrance at Sherman Avenue has eight median crossovers and about 20 businesses on its east, much more heavily developed, side. Signs and earth work just south of the hospital on the east side of the highway signal more development to come in that area.

The only traffic signals on the stretch of road are at Sherman Avenue, 1.6 miles north of I-20, and Bowie Road, 2.4 miles north of the interstate.

Smith said speed-limit changes must be preceded by speed studies and must be made by the state’s three-member transportation commission. The general practice in setting speed limits, though, is to follow rather than govern the flow of traffic, he said.

“What’s posted on the ground and how people drive are totally unrelated,” Smith said. “People drive the speed they feel comfortable.”

MDOT tries to set highway speed limits by national guidelines that say they should be about the speed at or below which 85 percent of drivers travel, Smith said. That level is determined by speed studies that can be done relatively easily, officials said.

“You don’t have to move the limit by but a little bit to increase the number of violators by a lot,” Smith said. “One of the indications that the speed limit is set too low is that you’re writing a lot of tickets.”

On five-lane roads with middle turning lanes, the transportation commission usually sets speed limits at 45 mph, Smith said.

Cities that request changes to speed limits on highways in their corporate limits and declare that they will enforce those limits have a good chance of getting their requests approved by the commission, Smith said. He added that he was aware of no formal requests for a study to change the speed limit along that stretch of road.

Driveway-access-control on U.S. 61 North is the least restrictive of the MDOT’s three types. To add driveways onto the four-lane stretch of road businesses must get permits from MDOT, permitting officer John McDonald said. Driveways cannot be closer than 25 feet to each other and, when they are added near crossovers, they must line up with the crossovers as closely as possible, McDonald said.

“We can deny access if we feel like there’s a safety concern,” McDonald said.

No plans are in the works to study adding traffic signals to the stretch of road, assistant district engineer for Warren County Carl Middleton said.

Before signals can be approved MDOT must perform traffic counts, which it generally does during “normal” times, while school is in session and not in its first two or last two weeks, and not during morning or evening rush hours.

“If a city thought a signal was needed, it would contact us to do the studies,” Middleton said. “It starts with a perceived need for a signal.”