It is no secret that preventing unsafe speeds is one of the most – if not the most – important things we can do to advance safe mobility for all. And we have a lot of proven ways to do just that. Surprisingly, though, one of the most effective ways to manage speeds for safety is mostly ignored. This largely overlooked, but massively effective approach is limiting the speeds that vehicles can move at – especially curbing uber-high, dangerous speeds.
That’s why we’re so excited and encouraged by the growing attention (finally!) toward Intelligent Speed Assistance (ISA), a particularly effective speed management tool. The technology is being used effectively in other nations and is highlighted in the U.S. National Highway Traffic Safety Administration’s (NHTSA) Countermeasures That Work. The National Transportation Safety Board (NTSB) recommended making ISA standard equipment in all new vehicles. The Road to Zero Coalition issued recommendations for vehicle-based approaches to prevent speeding, with ISA playing a central role. And new research from the Insurance Institute for Highway Safety (IIHS) shows that public acceptance of ISA is strong, reinforcing its readiness for wider use.
And now, localities and states are stepping up to the ISA opportunity too. In our September webinar, we learned about how New York City and Washington, D.C. are deploying ISA at the local level and how states are starting to embrace ISA policies to check dangerous “Super Speeding” on our roads. We hope these ideas inspire your community to take action with ISA too!
What ISA is (Briefly)
Active Intelligent Speed Assistance (ISA) is a vehicle technology that helps a driver stay within the posted speed limit by preventing acceleration above a certain limit. It does not apply the brakes; instead, it limits the vehicle’s throttle so that it does not speed up beyond the safety threshold set. That threshold can be configured (e.g., exactly at the posted limit or with a “grace” amount of a few mph over the posted limit), and ISA programs can allow for an emergency override. There are a few variations of ISA, but this discussion focuses on the active version (read more here).
Why ISA Matters for Vision Zero
While physically designing safe streets and setting safe speed limits are core to advancing Vision Zero, the efficacy of these strategies is not as strong when it comes to curbing some of the riskiest behaviors on our streets, including constraining known super-speeders who cause outsized harm. ISA can be used to target the most reckless behaviors at the source – the pedal!
“This is one of the best systems that are out there, one of the things that are going to have the most impact. And quite frankly, if you want to move the needle, you should do it with ISA.”
– Eric Richardson, Together for Safer Roads
ISA is flexible and can be used in important ways beyond curbing super-speeders, as cities and states are starting to do (examples below). This technology has a track record in public and private fleets not only to improve safety but also to lower insurance and repair costs. And especially for government fleets, this is a way to lead by example, improving safe driving, reducing speeding tickets issued and lowering liability costs. There is also increasing attention to high-risk drivers, such as teen drivers, voluntarily using ISA.
And, ISA is flexible in how it’s used. For instance, it dynamically limits speed to match the posted limits – in real time. This is a big difference from traditional speed governors, which only caps top speed in a static way.
NYC: ISA Evidence at Scale
New York City launched the nation’s largest ISA pilots on its own fleet in 2022 – spurred by strong advocacy from groups such as Transportation Alternatives and Families for Safe Streets, which urged Mayor Adams to act. The pilot covered an estimated 500 vehicles across 19 agencies and 21 vehicle types, ranging from electric sedans to garbage trucks.
The NYC pilot measured the efficacy of ISA on these vehicles as they traveled nearly three million miles over a year. The impressive findings among the fleet include the following:
- 99% of miles traveled were at or below the program’s set threshold speed,
- 64% decrease in speeding compared with similar fleet vehicles without ISA,
- Speeding dropped most on higher-speed roads: 49% reduction on 25 mph streets and 82% reduction on corridors with higher limits,
- Safety performance improved by ~95% among drivers with the worst speeding histories.
Read more in the NYC ISA Pilot Evaluation report.
As part of the rollout, NYC also piloted ISA on its school bus fleet. Early results showed ISA could seamlessly maintain safe speeds while transporting children, reinforcing its value for fleets carrying the most vulnerable road users.
Beyond safety, NYC saw other significant benefits for its fleet, including:
- Fewer traffic violations and crash claims,
- Less wear and tear on the vehicles,
- Improved fuel/EV efficiency.
NYC is using federal Safe Streets and Roads for All (SS4A) funding to scale it up further. And, ISA fits neatly into the City’s existing telematics and impressive safe-fleet transition plan.
Key Takeaways: ISA works well across mixed fleets (from dump trucks to school buses); shows measurable safety results quickly; pairs with telematics to focus on the highest-risk drivers and routes; and helps reduce costs.
Washington, D.C.: Start Small, Scale Fast
Washington, D.C. went from the initial idea to a live ISA pilot in about 12 months, beginning with a proof-of-concept on SchoolConnect buses that provide dedicated rides for registered students (less than 20 of 40 vehicles) and then expanding to hundreds of fleet vehicles across multiple agencies.
D.C.’s analysis of the effort led to the following understandings:
- Retrofitting with ISA is straightforward; it does not need years for planning or implementation, unlike many safety measures.
- “Grace” settings help with acceptance among drivers: D.C. set an absolute cap of 60 mph, then allows some small buffers (no excess grace amount for limits up to 30 mph; +3 mph between 30-50mph; and +5 mph between 50-60mph).
- The D.C. team expects ISA to cut crash costs and liability.
- Feet managers already report fewer crashes and speeding tickets – reducing repairs, claims, and overall risk.
- Educating operators and the public are helpful: DC provides drivers’ with a brief orientation and adds a rear sticker to the vehicles (“This vehicle can’t exceed the speed”).
D.C. fleet vehicles display this sticker to show they are ISA-equipped and speed-limited.
And starting in Fall 2025, D.C. will be the first U.S. city to act on a policy to install ISA in vehicles of some convicted dangerous drivers (more on this policy below). This is being integrated into D.C.’s broader fleet-safety work, including using telematics, measuring and sharing information for transparency, and using speed safety cameras.
Key Takeaways: You don’t need a giant program to start – fleets of any size can benefit from ISA. Pilot in a visible, safety-critical subfleet (school transport, child services). Measure impacts of pilots, learn from results and scale up accordingly.
“Super Speeders” Bills: Targeting the Riskiest Drivers
In an encouraging new trend, state legislators are increasingly taking up policy discussions about using active ISA for repeat or extreme speeding offenders, modeled on ignition-interlock programs. (Kudos to Families for Safe Streets for their nationwide leadership – read more about their efforts!) The momentum for ISA “super speeder” laws is real: D.C., Virginia, and Washington State have passed laws, while Connecticut is actively studying the issue. And several other states (Georgia, California, Maryland, Arizona) introduced bills last year that have not moved forward – yet!
The rationale is clear and convincing: traditional penalties, such as fines or license suspension, often fail to restrict dangerous drivers. In fact, roughly 75% of drivers with suspended licenses keep driving illegally. But ISA can be far more effective and less financially punitive, which is important for low-income people who are disproportionately affected by traffic fines compared to high-income drivers. And, ISA can better accommodate the reality that many people in the U.S. do not have good transit/walking/biking options, so depend on driving to get to work, school and other needs.
Here are important pieces we learned about in the webinar:
- The costs of adding an aftermarket, active ISA technology are reasonable: Approximately ~$4/day to lease and $100 to remove.
- Administrative burdens of running “super speeder” programs with ISA are modest and similar to alcohol interlock programs with startup in the $0.5–$1M range, estimated $100k/year of ongoing costs, and the need for 1 or even fewer full-time staff, as Families for Safe Streets estimates.
- These ISA “super speeder” bills are drawing bipartisan support in multiple states.
Key Takeaways: ISA for repeat offenders is workable and politically viable, as they target the most dangerous of the dangerous drivers with proven technology. This is a speed management tool that states can lead on, and locals can show their support by encouraging their states to pass such policies.
What Local Agencies Can Do Now
Your local community can take action in the following ways:
- Prioritize Safe Vehicles in your Vision Zero plan & activities. Recognize the Safe Vehicle component of the Safe System Approach in your Vision Zero Action Plan and develop actionable steps and measurable metrics – find out how.
- Lead by example adding ISA to your municipal (or state!) fleet. This is low-hanging fruit and a proven, fast-acting way to reduce dangerous speeds. And this can be done as part of your regular procurement cycle, replacing or upgrading your fleets. So reach out to your fleet manager and get on their radar before the next procurement or replacement cycle is coming. Help them see the safety – and cost – benefits of ISA on fleets and be sure to add this to future specifications and budgets. And if new funding is needed to help cover startup costs or accelerate adoption, check out Safe Streets and Roads for All (SS4A) or other grants. What a way to lead by example!
- Scale up over time. You may start with one agency, then expand to all public fleets over time. And, you can extend ISA implementation to contractors to your city through bid specifications, helping set more precedents and normalizing this important and readily available safety feature for vehicles that spend a lot of time on the roads.
- Support Super Speeders legislation. Encourage your state leaders to follow the progress already underway in New York (first bill introduced), Washington State, Washington, D.C. (law passed in 2024 and set to launch in 2025), and Virginia (legislation passed in 2025) by championing policies that require ISA for the most dangerous repeat offenders. Find ways to support safety initiatives, including letters of support. Invite lawmakers to join the Families for Safe Streets Super Speeders Roundtable (stay tuned for the announcement) to help advance this life-saving legislation.
Intelligent Speed Assistance isn’t a new idea – it’s a proven safety tool. What’s new is how eagerly U.S. communities are starting to put ISA to work in order to advance their Vision Zero goals. New York City’s ISA fleet pilot has shown measurable safety and cost benefits; Washington, D.C. school bus pilot proves ISA programs can launch small and expand quickly; and support at state legislatures for policies to rein in dangerous “Super Speeders” is demonstrating bipartisan momentum.
We hope your community will take steps, too, to benefit from this practical, cost-effective tool for safe speeds.
These lessons came to life thanks to insights shared by Eric Richardson of Together for Safer Roads, Charlie Wilson from Washington, D.C.’s Vision Zero initiative, and Amy Cohen of Families for Safe Streets. We’re grateful for their leadership and for demonstrating how taking action for safer vehicles – specifically through ISA – can advance Vision Zero goals.