This is called the tus-tus in Hebrew. We would call it a scooter, a Vespa, a motorbike, etc. Here it's the well-known, cheaper and ubiquitous alternative to a car. Cars are ridiculously expensive in Israel, with killer VAT (value-added tax) so your basic $19,000 Toyota in California is $40,000 here. Clearly the tustus is cheaper, uses less gas, costs less to maintain, and is waaaayyyy easier to park.
I don't know why it's called a tustus. Speculation in my ulpan is that it is related to latoos, to fly, which pretty much describes how they move in traffic.
Judging from the way they maneuver through traffic, the tustus is also a quicker mode of transportation in rush hour, as well, although that speed and maneuverability come at what I deem too high a risk -- the risk of other drivers hitting you. Tustus vs. car or bus.....the tustus loses every time due to the laws of physics: bigger smashes smaller.
Tustus ownership isn't limited to young folks, although they seem to be the majority of riders. In one of those why-didn't-I-bring-my-camera moments, we watched a stout middle-aged chasid fly down Derech Beit Lechem on his tustus one morning, peyot and tzitzit and jacket streaming behind him. The FexEx couriers and the pizza delivery guys all arrive by tustus with their cargo lashed in carry-boxes behind them. Like all other Israeli motorists, the tustus driver can also talk on the cellphone: it's a simple matter of jamming the cellphone between the ear and the helmet and talking while riding--trust me, we saw that one also.
Their very maneuverability, though, makes them dangerous in the hands of the caution-impaired. I crossed Emek Refaim in the cross-walk one fine day, secure in the knowledge that the first vehicle to my left was a bus, stopped for the pedestrian traffic in the cross-walk. As I reached the middle of the road, I caught something in the periphery of my left eye, and instinctively took a step back, thus saving myself from becoming tustus road-kill. The tustus driver hadn't wanted to wait for the bus to proceed, so she swerved into the on-coming traffic lane and accelerated---almost killing the first pedestrian in the crosswalk, me. (I know it was 'she' because I very clearly heard her say, "Shit!" in English as we nearly collided.)
Cheap, maneuverable, cute, dependable -- but you'll never get me on one. I'd spend the entire trip worrying about cutting off an Egged bus and ending up a messy smear on the roadway.
I've received more emails from friends concerned about terrorism here. I tell them repeatedly that on a day-to-day basis, we're in more danger from the traffic than from anything else. This is something I'm thankful for--traffic problems can be fixed. I'm not so sure I can say the same thing about the neighbors who've been so thoroughly indoctrinated to hate us.
Photo courtesy of http://www.gsmotorworks.com