What does this sign mean?

Explanation: You will need to slow down. At hump bridges your view ahead will be restricted and the road will often be narrow on the bridge. If the bridge is very steep or your view is restricted sound your horn to warn others of your approach. Going too fast over the bridge is highly dangerous to other road users and could even cause your wheels to leave the road, with a resulting loss of control.

Category: Road and Traffic Signs

References: The Official DVSA Guide to Driving: Section 6, Highway Code: Page 109, Know Your Traffic Signs: Page 12