What does this sign mean?

Explanation: You'll need to slow down. At hump bridges, your view ahead will be restricted and the road will often be narrow. If the bridge is very steep, sound your horn to warn others of your approach. Going over the bridge too fast 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 Riding: Section 7, Highway Code: Page 109, Know Your Traffic Signs: Page 12