First of all if she’s traveling from one city to another then it’s not permissible for her to travel without a male mahram. If it’s within the city limits then there’s no problem.
Nobody can combine asr with maghrib, not even travelers.
She has to pray all the prayers on time. She must stop on the way and pray Asr on time before leaving work.

sheikh my friend does a job & she has 2 travel a few hrs journey.wen she returns home asr time is not due & wen she reaches home magrib azaan is called.so in such a case can she combine prayers. If she is not able to pray asr, on time is she sinful?Wat can b done in this case.plz advice.