I'll do my best to answer this without being totally cynical.
Okay, when you enter the department you start earning career points, from each medal you get to each year you have on the job to even integrity review points. These points vary in number, an EPD medal is worth about .01 of a point, yes, in order to get one point with EPD's you need to have 10. EPD's are usually easy to get, I had around 25 or so EPD's. After a certain amount of time you can use these points for a transfer. Usually this is used for precinct to precinct. But these points can be used to get an "Interview" for the "detail" that you would like.
For a significant amount of reality - if you have a "hook" in the department, a rabbi of such that can help you, it is almost a surety you'll get the interview, and transfer. Your summons activity MUST be good! This is not an easy feat. Never do you want to write more than guys usually do in your precinct, otherwise you'll find your locker in the trash - yes boys and girls cops really don't like writing you - these are called productivity goals - some people call them quotas - but alas quotas are illegal
You'll have to be a good boy, disciplinary problems which incur CD's (Command Disciplines) is not a good way to get into highway - we're a regimented unit - well, in my opinion.
The way it used to be, and still may be - when you get transferred to highway you'll get a temporary transfer from your precinct for 90-days and you'll be sent to "Wheel School" at Floyd Bennett Field. If you flunk out of wheel school, you're done - back to your precinct and back to patrol. If you pass, then you are officially transferred and you may now make the $2000 investment into your new uniform - yes we pay for our uniforms - all the leather.
If you get promoted, and you should strive for that - you will then be transferred to a precinct to work as a boss for at least six-months. Can you get back? Well if you were there as a cop and made good connections, especially with guys at the district (at Hwy 3), then you should have no trouble - but there has to be a slot open for a sergeant. But if your hook is "dead", then it may take some time. It helps though that you were a cop in the unit, because now the job doesn’t have to train you in all the aspects, especially AIS - freshen up your algebra!
Yes the sliding drill is reall - the instrutors wet down the grassy area along the flightline, you hit the throttle at around 20-25 mph and then all rear brake - the wayou you slide, or control braking is ll up to the skill you have. This is usually towards the end of wheel school. Wheel school is a NO BS school - screw up once and you're gone. Even when I got there and knew how to ride, I was asked if I ever rode, I said no because they hate getting bad habits from old salts - but I had a wheel license, I told them I was scooter qualified which back then got you a wheel license from DMV.
Your first day in wheel school you place the front wheel against a barrier laid across the ground, and you do clutch exercises, popping the front wheel onto teh wood without stalling or going over the wood. If you know how to ride it's an easy task - but it is fun to watch the guys not only learning how to ride a bike, but learning how to use a clutch for the first time.
This could go on and on, but if I haven’t been more specific, just ask and I'll elaborate as much as possible.