• MDZA@feddit.uk
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    1 year ago

    There are quite a few 20 mph roads near me where the only incentive to slow down is to avoid being caught be a speed camera.

    The roads are wide and straight for long stretches, and going at the 20 mph limit just means you become an obstruction for the rest of traffic, even buses and lorries.

    The design of the road and posted speed limits are sending mixed messages.

    • apprehensively_human@lemmy.ca
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      1 year ago

      There’s a concept in road design that says the engineer must first determine the design speed, which is basically how fast they want traffic to be able to flow. This part of the process is generally not part of any public hearing or put to a vote by public officials - it is just decided on and then they move on to the next step.

      There’s also a prevailing concept in road design that seems to indicate that high traffic speeds are a design issue, but low speeds are an enforcement issue. The road is designed to accommodate the highest amount of traffic anticipated in the future without really thinking about if that’s even a good fit for the area.

      Once the road has been built to exacting standards (which means it is far too wide and flat,) the city steps in and slaps a speed limit on it, often at odds with the design speed.

      When residents get worried about all the speeding cars, they petition the city for a traffic study to see if anything can be done. The engineers conducting the traffic study determine that the road is capable of handling higher speeds than the current limit, and so to cut down on speeding the recommendation is to increase the posted limit.

      It’s amazing to me how much influence the engineering team has on the design with basically no accountability. You can try to reduce speeding by putting up speed traps and police patrols, but at the end of the day people will drive as fast as they are comfortable with and that is often a result of the design of the road they are driving on.

    • Metal0130@lemmy.world
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      1 year ago

      You may enjoy the YouTube channel, Road Guy Rob. He covers a lot of these issues and more. It’s a niche channel for sure, but can be fascinating if you’re into that kind of thing.

    • orcrist@lemm.ee
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      1 year ago

      I can’t really make sense of what you’re saying. If the road is straight and wide but also has a low speed limit, that’s not sending mixed signals. Rather, it’s suggesting that you should drive slow even though your instinct tells you that you could drive quickly, presumably because there are either obstacles creating blind points that could lead to pedestrian or bicycle involved accidents, small children playing nearby, or cars turning onto or from side roads that you might strike if you’re driving at the speed that your gut tells you is safe.

      In other words, you shouldn’t trust your gut when deciding how fast is safe on a road because your gut is often mistaken about the finer points of road design.

      Also, you wrote that a slow driver would be an obstruction to other vehicles including trucks. I think you were wording that as a bad thing, but in reality it’s a good thing. One reasonable driver can force a dozen bad drivers to slow down.