All eyes on ISA: reducing vehicle speeds can cut collisions – and CO2

By 2050, the European Union (EU) wants to completely eradicate road fatalities. That’s a bold vision, but one that the EU is committed to by implementing safer infrastructure and vehicles, reducing speeding, distractions and drunk driving, and enabling faster post-crash care.

One of the most significant technologies to emerge as a result is Intelligent Speed Assistance (ISA), a safety feature that helps drivers stay within the speed limit.

From July 2022, ISA became a mandatory feature for all new cars, vans, trucks and buses sold in the EU. This summer, the regulations will change again to include all newly registered vehicles, even those launched to market before July 2022. The regulations will apply in the EU’s 27 member states, as well as Norway and Switzerland.

In the United States, a number of ISA pilot programs have been initiated – such as Columbia District Council’s new safety bill that imposes ISA installation in the vehicles of drivers who commit serious speeding crimes. In California, State Senator Scott Wiener, has proposed a bill that could see ISA come into force by 2027.

While there isn’t an American-wide consensus on ISA installation, the National Transportation Safety Board has recommended to the National Highway Traffic Safety Administration that all new cars sold in the US should contain ISA.

What is Intelligent Speed Assistance?

ISA uses cameras and precise location and mapping technology to pinpoint where the vehicle is at any given moment, comparing its actual speed with the limit for that road. For roads with varying speed limits or temporary speed restrictions, ISA’s cameras can read speed limit signs, while maps help when the road signs might be obscured due to weather or traffic.

The legal speed limit is always on display in the driver’s line of sight – and is the same as the limit posted on road signs. This helps drivers remember the speed limit along their entire route.

If a driver exceeds the speed limit, ISA systems either alert the driver through an acoustic or haptic warning, or intervene and assist the driver in abiding by the speed limit. These so-called speed control functions can currently be overridden by the driver.

In Europe, EuroNCAP, the car testing program, awards higher scores in its tests for vehicles that have speed assistance systems equipped.

What effect will ISA have on speeding?

Speed is a major contributing factor in road fatalities and collisions. According to the European Road Safety Observatory, “10 to 15% of all road crashes and 30% of fatal injury crashes are the direct result of excessive or inappropriate speed”. The report found that even a 1km/h speed reduction across all EU roads would save more than 2,000 lives per year.

“Speed, along with alcohol and the non-wearing of seatbelts is one of the major risk factors in road safety,” Professor Oliver Carsten, from the Institute for Transport Studies at the University of Leeds, told the UK Parliament’s Transport Committee. 

“A 1mph change in the mean speed of traffic on a road is associated with a 5% change in the number of injury accidents on that road. If all vehicles in Great Britain complied with current speed limits, there would be a 29% reduction in injury accidents and a 50% reduction in fatal crashes”.

Professor Carsten pointed to a similar study in Adelaide, South Australia, that found that vehicles traveling at 10km/h over the speed limit were four times more likely to be involved in a collision than those traveling at the limit.

On the significance of ISA, Professor Carsten, who modeled the effect of ISA over a 60-year period, added: “This has been referred to as the biggest intervention since compulsory wearing of seatbelts and will probably be more effective than that. The estimate is that a minimum of 25,000 lives will be saved over the evaluation period, but this is conservative. We are talking about an extremely important safety package.”

Could ISA cut emissions?

Saving lives and reducing serious collisions is, obviously, the key benefit of ISA, but the technology brings another bonus – a reduction in carbon emissions. Road transportation is one of the most significant sources of greenhouse gas emissions in the EU (in 2020, 77% of EU transport emissions came from road travel). Similarly, in the United States, emissions from trucks and passenger cars are responsible for 80.9% of all transportation emissions.

According to US Department of Energy data, traveling at 60mph is 25% more efficient than driving at 75 mph. “At speeds over approximately 35 to 45 mph, if a vehicle reduces its speed by 5 mph, its fuel economy can increase by about 5 to 10%, because air resistance, or drag, increases exponentially as a vehicle goes faster,” stated a report by the United States Government Accountability Office.

Research conducted by Professor Carsten showed that ISA “generated an immediate 5% fuel saving for motorway driving” and reduced CO₂ emissions by up to 5.8% on 70 mph roads. According to the European Transport Safety Council, “properly enforced national speed limits could cut carbon emissions”, claiming one million saved tons in the UK and three million tons in France. In Germany, where some stretches of the autobahn have no speed limit, a 100 km/h speed limit would reduce CO₂ emissions by 10%, while a 120 km/h limit would reduce emissions by 20%.

As governments battle with the need to reduce carbon emissions and make the roads safer, the incorporation of ISA systems could help achieve both aims simultaneously.