Another Riddle!

[Adam]

Yeah, it's another riddle. Enjoy.

A truck, a massive one, is driving down the highway, The truck happens to come across a small bridge. Knowing the route well, the driver knows he cannot stray off the path, as that will take too much time for his delivery. The maximum weight for the bridge is 6 tons. Not knowing this, the truck driver continues driving, though his truck is exactly 6 tons. No more, no less. A butterfly lands on the truck. The bridge does not crumble, the driver just continues driving and the bridge is fine. How is this possible?

(Any moderator feel free to delete this post, it no longer serves a purpose.)

[Banana_Cannon]

english tons and american tons.

[Adam]

Sorry Bananna Cannon, but the measurements are both the same. All American tons.

[Slash]

by the time hes across the bridge, he has lost gas which takes a toll on ur weight?

[nickmcski]

Bridges are rated lower than what they can actually Handel. So even if it said the maximum was 4 tons, it can still handel atleast 4.5 tons.

[Adam]

Congratulations Slash, you solved the riddle. Thank you to everyone who came close, it has been very fun coming up with this riddle. More coming soon!

[Handyman]

Also the bridge may be designed to handle 6 tons of load when it is on one place, since the truck is moving and creating forward movement the is not a total of 6 tons anymore. So depending on the speed the load is lighter.
Also here in the Netherlands we use a safety measurement in constructions, we multiply the variable weight by 1,5 so actually the bridge can take 9 tons.