The Drive: Speeds can differ on opposite sides of road

The speed limit on County Road 81 — also known as Bottineau Boulevard — between Bass Lake Road in Crystal and Interstate 94 in Brooklyn Park was 55 miles per hour on both sides of the road until last summer, when Hennepin County started a reconstruction project on the northern end of that segment.

During construction, northbound traffic in that area was reduced from three lanes to two — and sometimes one — and the speed limit was dropped to 45 mph. When the cones and barrels were picked up last fall, the speed limit on the northbound side remained at 45 mph even though the southbound side is posted at 55 mph. That's surprised a few motorists.

Drive reader David thought it was odd that one side of the road would be posted with one speed limit while the other side had a different speed limit. Is it possible that the 45 mph sign was a leftover from construction? he asked.

The Drive posed the question to Colin Cox, the county's senior communications specialist for transportation. He said that "it's not unusual to have two different speeds for northbound vs. southbound traffic in an area."

In this case, the speed limit is lower on the northbound side because of construction that is occurring in the area of Interstate 94, which is about a half-mile north of 63rd Avenue.

Last year the county installed a noise wall on the east side of Bottineau between 63rd Avenue N. and I-94 and put in the lower speed limit to slow down northbound motorists before they hit the construction zone. Since the construction was primarily on the east side of County Road 81, the speed limit for southbound motorists was left at 55 mph.

Construction is on hiatus for the winter, but come this spring, work on adding lanes, improving access and connections to side streets and frontage roads, putting in crosswalks and new traffic signals, and improved stormwater systems will resume. Most of the work will be between I-94 and W. Broadway and again will impact northbound traffic more than southbound traffic. Therefore the county left the speed limit as 45 mph over the winter.

When construction is complete later this year, it is possible the speed limit on the northbound side will be reposted to the former 55 mph — but that is not a certainty, he said.

Even without construction, speed limits can vary from one side of a road to the other. In the case of Bottineau, railroad tracks run parallel to the road on the west side. On the east, there is a frontage road and there are a handful of points where traffic enters and leaves the highway.

Cox said those types of characteristics, along with variables such as traffic volume, differing traffic movements, whether there is a school or big attraction on one side of the road, and whether there is a center median or not can influence whether a speed limit is higher or lower.

Drivers should not assume that both sides of a road are posted with the same speed limit, Cox said. He said drivers should think of each side as if it were a separate roadway, and of course, "pay attention to the signs."

Cox also recommended that drivers who rely on navigation apps to follow the speed limit should keep them updated. If they don't and speeds change, they could find themselves going too fast.

Follow news about traffic and commuting at The Drive on startribune.com. Got traffic or transportation questions, or story ideas? E-mail drive@startribune.com, tweet @stribdrive or call Tim Harlow at 612-673-7768.