All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Whether or not it is permissible for you to take that allowance depends on the contract between you and the employer in accordance with the regulations they have. Do they condition that for the employee to deserve transportation allowance he should be in need of it and spend it in transportation or not? If they condition that in order to take the transportation allowance you must spend it in commuting to and from work, then you are not entitled to take it since you do not need it, as the Prophet said: “The Muslims must fulfill their conditions.” [Abu Daawood and at-Tirmithi]
However, if they do not stipulate that, then there is nothing wrong with you in benefiting from it.
Allah knows best.