"Are able." the police are able to respond. The police officer is.. The police station is... The officer is.... BUT: Police is a plurale tantum, a word with no singular form. https://ell.stackexchange.com/questions/22142/police-are-or-police-is
Although arrest does mean stop, like in the example of "cardiac arrest" or "arrested development", the common usage in English is to "take into custody". If a policeman pulls a driver over, then after talking to him takes him into custody, we would say that first he "stopped" the driver then he "arrested" him. It doesn't appear to work that way in Hebrew. If a שוטר pulled you over while driving, and you said the sentence in this exercise, you would likely be asking him why he was stopping you, not why he was "arresting" you.
Never heard of this sentence, funny (and sad). Not trivial to translate to Hebrew. If the base phrase is for driving under the influence of alcohol / drugs, there are some phrases in Hebrew.
ll נהיגה תחת השפעת סמים; can't replace with black / Palestinian
ll נהיגה בשכרות: well, you can try נהיגה בשחרות! Some would think it's very good (changing just one letter, with a similar sound), but I find it way too opaque. נהיגה בפלסטיניות doesn't reflect the base phrase sufficiently strongly.
What I would try is to play on נוהג בעודו שיכור. I'm not sure it's actually used, but it sounds natural enough. So you can do נוהג בעודו שחור/פלסטיני.
Although there are cases that זַ֫יִן and צָדֵי alternate, this is not the case with these two roots here. Examples are זָעַק and צָעַק, both to shout, עָלַז and עָלַץ, both to rejoice and the roots זער and צער, both to be small, in Modern Hebrew f.e. used in זִעֵר to miniaturize and צָעִיר young.
I'm not Israeli, I'm learning Hebrew as well, but Ulpan Noya has a video on this called "are Israelis even speaking Hebrew?" It addresses pronouncing numbers, but she says that it's common in other areas (don't forget to look in the video description for more details about this): https://youtu.be/ts4r7-JpIes
Well yes, when a word begins with the same vowel as the word before it ends, its glottal stop (if pronounced at all anyway) can be overridden and a long vowel is formed. The glottal stop represented by א is mostly used before a stressed syllable (מִקְרָאִי biblical [mikraʔi]), but is elsewhere for most speakers silent.