maintain: i.e., stay within (the limits)
TFD: 3. to keep in a specified state, position, etc.
ODO: keep (something) at the same level or rate
When you have not exceeded, i.e., stayed within the speed limit,
You maintained the speed limit.
Use case:
dailyindependentnig: FRSC urges motorists to maintain speed limits
Miller et al. Community Policing: ... maintain speed limit
Wild Trail in Bengal: maintain speed limit of 20 kmph.
[EDIT]
He never gets tickets because he always maintains the speed limit.
To win the match, Tiger Woods must maintain the 4 strokes on the twelfth hole limit.
To prevent freezing, maintain within -20 degrees centigrade.