The most congested interchanges on the U.S. highway system is the Tom Moreland Interchange in north-east Atlanta, GA, a.k.a. “Spaghetti Junction.”
So says the American Transportation Research Institute (ATRI) in its annual listing of the top 100 bottlenecks for trucks. Here are the top 10 locations on the ATRI list for 2015:
- ATLANTA, GA: I-285 AT I-85 (NORTH)
- CHICAGO, IL: I-290 AT I-90/I-94
- FORT LEE, NJ: I-95 AT SR 4
- LOUISVILLE, KY: I-65 AT I-64/I-71
- HOUSTON, TX: I-610 AT US 290
- HOUSTON, TX: I-10 AT I-45
- CINCINNATI, OH: I-71 AT I-75
- HOUSTON, TX: I-45 AT US 59
- LOS ANGELES, CA: SR 60 AT SR 57
- HOUSTON, TX: I-10 AT US 59
Clicking on the item listed on the ATRI page will result in a download of a map and charts (.PDF format) showing the average speeds on the interchange over the course of the day, broken down in a 24-hour-by-hour frequency. This should help in trip planning.
Why This is Important to All Drivers
From a safety perspective, interchanges account for less than 5% of all freeway
lane-miles, but 20% to 30% of freeway truck accidents occur on or near ramps.
The good news is that one study found higher volume ramps had lower rates of truck accidents per truck-mile of travel.¹ It also found approximately the same number of accidents for both the merge and diverge ramps.
There is a higher frequency of accidents, particularly rollovers, at loop ramps (as cloverleafs). Loop ramps are designed with the intention of safety because they reduce the chances for conflict, but can be a problem for trucks with a higher center of gravity.
Authorities say the semi-truck was likely traveling too fast for the exit from I-435 to I-70 when it overturned and slid into the guardrail. The cab of that truck was split in half.
The driver of that truck, a 24-year-old man, was killed. Police have not released the identity of the victim, however, they say he was not from the area.
Diamond interchanges are safer for trucks, especially if the ramp is straight.²
Here are some Tips to avoid ramp and interchange collisions and rollovers:
• Plan your route. Multi-level interchanges can be confusing, especially at night.
• The small exit number sign on top of a larger directional sign is always on the same side as the exit. The sign below tells us to move to the left lane for Exit 32.
• Signal intentions well before the exit or when you can read the final exit sign.
• Be in the proper lane leading up to the exit ramp and be mindful of cars that may attempt to cut you off and get around your truck.
• Stay 100% focused. Keep both hands on the wheel. Be aware of surrounding traffic.
• Look for backups or vehicles stopped on the ramp. Be ready to slow or even stop. Some of the deadliest collisions have occurred when a truck rear-ended a slow or stopped vehicle in the ramp. Maintain good following distance, keep plenty of space in front, and leave yourself an out.
• Look for speed limit signs before curves and keep the speed of the truck at least 10 MPH under the posted or advisory speed limit signs. Posted ramp speeds are not for trucks. Adjust speed even more when weather conditions as ice, snow, rain, and wind are of concern.
• Be cautious of the vehicle speed when coming from a sloped bank to a flat roadway. Don’t start accelerating too soon. Use the acceleration lane to get up to speed before merging into traffic. More crashes occur leaving the interchange as entering it.
Recall the saying, The bottleneck is at the top of the bottle. Use your head and everything goes much smoother.
Thank you for reading this. Have a super-safe day and weekend.
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