Weight limit roads / bridges are exceeded by our Lightnings - how will these EV trucks handle restrictions ?

[Zaptor]

TBH if I see that and need to cross, I'm doing it *fast* so if the bridge goes, there's still a chance I make it to the other side...
-Zap

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[LancerBoom]

Where I live, a sign like that is an axle limit. Sign says 3 ton limit X 2 axles = 6 ton vehicle weight limit. This follow FMCSA rules, California may be different.

Iowa DOT rules state for a sign like that: “Regardless of how much of the total weight of the vehicle is actually on the bridge, the gross weight of the entire vehicle must be equal to or less than the limit on the sign.”

if it is an axle limit, the sign must say “Axle weight limit “ or have silhouettes of different configurations with the limit shown for each configuration.

Just looked at South Dakota’s rules and basically says the same thing.

 

[Sandman]

Engineer (non-civil, but I love studying all engineering and have for decades) here.

I assure everybody, there's no guessing going into any bridge. The numbers are thoroughly evaluated by the designer, then re-checked by independent peers - usually through local government. Yes, the final figures will be conservative by some standardized amount, which is a very good thing. We need to account for age, weathering, traffic effects, wildlife impact, minor flaws during construction, maintenance (or lack thereof), etc.

As for bridge capacities making real-world sense, you'll have to talk to whoever funded the thing for that. I agree that 3 tons is no longer adequate, nor has it been for quite some time.

Would I drive a Lightning over that bridge? Meh, probably, if I'm not hauling or towing. If the bridge is in good shape then another 1000 lbs (33%) should be well within its margin. But I also realize that the sign isn't just a warning, it's a statement of liability if I break something

 

[tommyb]

Engineer (non-civil, but I love studying all engineering and have for decades) here.

I assure everybody, there's no guessing going into any bridge. The numbers are thoroughly evaluated by the designer, then re-checked by independent peers - usually through local government. Yes, the final figures will be conservative by some standardized amount, which is a very good thing. We need to account for age, weathering, traffic effects, wildlife impact, minor flaws during construction, maintenance (or lack thereof), etc.

As for bridge capacities making real-world sense, you'll have to talk to whoever funded the thing for that. I agree that 3 tons is no longer adequate, nor has it been for quite some time.

Would I drive a Lightning over that bridge? Meh, probably, if I'm not hauling or towing. If the bridge is in good shape then another 1000 lbs (33%) should be well within its margin. But I also realize that the sign isn't just a warning, it's a statement of liability if I break something

I am a practicing Civil Engineer who has managed road and bridge engineering and maintenance departments so I'll chime in. Sandman is correct.
If a weight restriction on a given bridge is exceeded will the bridge fail and collapse? Likely not, but depends on many factors like how much weight, how often the bridge has experienced high loads, the bridge's structural rating, etc.
In the situation above I'd probably do what Sandman described. If something catastrophic were to happen, hopefully no injuries and also hope you have really good insurance because you will be legally liable.
BTW, if a posted sign just says "Weight Limit," it means the total combined weight of the vehicle plus any load it's carrying. Or a posted sign could reference axle loads which are just that, and loading will be posted on the sign for one or more axle combinations, e.g. single, tandem, tri, etc.
Be safe out there...

 

[pullinggs]

TBH if I see that and need to cross, I'm doing it *fast* so if the bridge goes, there's still a chance I make it to the other side...
-Zap

Part of me really loves this... the other part says 9.8 m/s^2.

 

[InTheCloud]

The gas F-150 has a GVWR of 8500 pounds with the max tow package. Unladen the gas truck weighs 4705 pounds which is 2.3 tons.

For comparison my Kia EV6 AWD (270 EPA range) weighs 4795 pounds (2.3 tons) so it would have no problem on the bridge — it basically weighs as much as the gas F-150. So EVs are indeed heavier but not by an insane amount given how many people drive big SUVs.

A BMW 3-Series M340i XDrive is 3951 lbs. Cars are just heavier now.

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