On Thursday, New York Governor Andrew Cuomo vetoed a widely supported bill that would have legalized electric bicycles and scooters. The bill was the result of extensive negotiations and compromises that sought to balance a set of competing interests. But in vetoing the bill, Cuomo cited an interest that he felt hadn't been properly considered: public safety, specifically the lack of a helmet requirement.

By waiting until the end of the year to veto the bill, Cuomo has left the legislature without an opportunity to override this veto, meaning the whole process will have to start again next year.

The whole situation has been extremely complex due to the number of technologies and constituencies involved. On the tech front, there are several types of vehicles, including the pedal-assist e-bikes we test rode earlier this year. These require the user to pedal before the motor will act and are typically limited to speeds of just under 30mph. Separately, there are electric bikes where the motor will operate without the user doing anything other than operating a throttle, which have become favorites of the legions of food delivery people in New York City.

Technically, however, the latter are motorized vehicles, and therefore subject to vehicle registration rules—or they would be, if the state's vehicle registration rules allowed that. This has enabled the police to fine delivery riders at will, leading to accusations that the lack of policy was anti-immigrant and/or a form of class warfare.

Finally, there are scooters and related items like motorized skateboards and balance boards, which also fall into the motorized vehicle category. Here, the push for legalization came largely from the scooter rental companies. But a feature central to their business model—store the scooters in public spaces—raised fears of chaos on the already crowded New York City sidewalks. These would also compete with the popular citi-bike program that rolled out with heavy government support.

In addition to the question of what you can ride, there's the issue of where you can ride it. New York City has put a lot of effort into producing space for bicyclists to ride free of the dangers provided by motorized vehicles, putting in physically separated bike lanes on streets, in parks, and across many of the city's iconic bridges. In the absence of any rules, these lanes have become free-for-alls, leaving bicyclists dodging powered vehicles that could travel well in excess of 20 miles an hour uphill.

Balancing all of these complications probably explains why the legalization process has been so slow in the Empire State. But this year, the legislature managed to forge a number of compromises. All of the vehicles would be legalized without requiring state registration. Electric scooter rentals would be prohibited in Manhattan; access to the remaining markets in the state was enough to get the rental companies on board. And, while electric vehicles would be allowed in most bike lanes, they'd be kept off the popular loop around the Manhattan waterfront.

Food deliveries would occur without incident.

But nearby Elizabeth New Jersey had legalized scooters earlier in the year, only to see a rider killed in a collision with a tow truck shortly after. That may have helped motivate Cuomo's demand for mandatory helmet use to be included with any bill. (The state mandates helmets for bicyclists under the age of 14.) The relatively high speeds achievable on some bikes and scooters would provide further motivation.

Still, that doesn't explain Cuomo's decision to hold his veto until after it was too late for the legislature to modify the bill during this year's legislative session. Due to the wide support it achieved (it passed the state Senate by a 56-5 vote) and the number of constituencies interested in seeing something pass, it will almost certainly be back in 2020.