The only time allowance would not refer to money is with the idiomatic expression make allowance for X, meaning to include X in your plans, or to adjust for some factor X.
The engineers made allowances for the loose soil when designing the bridge.
We have to make allowances for his lack of experience.
With your example you would instead use the common verb "to allow"; however in this case this would ordinarily imply some person who is granting you permission (not a traffic light):
I stood at the crossing and waited until the policeman allowed me to cross.
I stood at the crossing and waited until I was allowed to cross.
If you are just waiting on the light to change, you would instead say:
I stood at the crossing and waited until I could/was able to cross.
I stood at the crossing and waited for the light to change.