Is it permissible for a Muslim to pray in his car while sitting – given the inability to perform ablution (wudu’) – during the Dhuhr and Asr times; due to studying at a Jewish college, and finding it difficult to pray standing or to maintain ablution there?

You should avoid studying at the aforementioned college, if possible, due to the prevalence of objectionable acts (munkarat), the difficulty of fully performing religious rituals, and the potential harassment you might face. However, if you are compelled to study there because no other option is available, and the issue is merely their dislike of seeing someone praying, then you must perform the prayer at its due time after fulfilling its conditions, such as ablution (wudu'), even if inside the bathroom, as the Prophet (peace be upon him) said: "The prayer of none of you is accepted if he has a ritual impurity until he performs ablution." If you are unable to perform the prayer during working hours, and work ends before Maghrib with sufficient time to perform Dhuhr and Asr, then combine the two prayers by delaying them (jama' ta'kheer) due to hardship. However, if studying there results in neglecting prayer, then you must abandon it and seek another means of study or livelihood; "And whoever fears Allah – He will make for him a way out And will provide for him from where he does not expect."