Running with the big dogs

This photo was taken on I-275 southbound near Detroit. Lots of tractor-trailers were present on this highway on a weekday evening. The top speed limit in Michigan for cars is 70 mph, surprisingly allowed even on this roadway in the Detroit suburbs. Michigan however has a lower maximum speed limit for trucks: 60 mph. Ohio and Indiana also have split speed limits on their rural interstates. I like this idea: Even though the trucks generally do go faster than their speed limit, they generally do not travel at 70 mph, which makes it easier for cars to get around the trucks. Also on highways with 3 or more lanes in the same direction, trucks are not allowed in the far left lane. The situation pictured above was a little dicey, because there was essentially no left shoulder, but rather only a high Jersey barrier dividing the opposing roadways. Still, we got through with no difficulties.

Median crossover crashes a problem in Kansas

I noticed a small news story in USA Today about a recent spate of deadly crossover crashes in Kansas. Highway engineers were quoted as saying they designed the medians of divided highways to be wide enough to enable drivers to regain control if they strayed off the left side of the road. There was speculation that rising traffic volume may have something to do with the increase in these crashes and also talk of the need for some kind of barrier down the center of the medians.

I've noticed that even on many Interstate highways that the typical grass median is not wide enough, in my view. For example, West Virginia allows 70 mph travel on I-64 west of Charleston, but the median is only about 2 lanes wide (if even that much). Worse, it is V-shaped in cross section, with the center of the median well below pavement level. This means that almost any vehicle angling into the median at legal speeds would be likely to flip over. Imagine being rammed head-on by an upside-down car!

Some states including the Carolinas have taken steps to alleviate the problem. Even on highways with wide medians, cable-type guardrails are installed in the center to prevent cars at least from crashing through. I doubt that tractor-trailers would be stopped by these, however. Data from South Carolina show that deadly crossover crashes have been reduced.

Locally, there is one older freeway that raises eyebrows for me. It has a rather narrow level grassy median for most of its length, but on one half-mile segment that passes beneath a highway bridge and a railroad bridge, the median narrows down to a cement curb only about two feet wide. In this day of Jersey barriers (the ubiquitous curved concrete dividers where there is no space for a proper median), I am surprised that the state of Virginia has done nothing about this roadway segment. I even more surprised that apparently very few deadly crashes have occurred at this spot during the 15 years I have lived in the area.