Intelligent Speed Adaptation trials

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Intelligent Speed Adaptation trials
General information
Type: Field operational test
Tested system/service: Intelligent Speed Adaptation
Countries: UK ? test users
2 partners 22 vehicles
Active from 01/2001 to 2008/09/08
ISA on DfT website
Oliver Carsten
University of Leeds
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Intelligent Speed Adaptation (ISA) is a system that provides, within the vehicle, information on the speed limit for the road currently being travelled on. That information can be used to display the current speed limit inside the vehicle and warn the driver when he or she is speeding (i.e. Advisory ISA); it can be linked to the vehicle engine and perhaps brakes to curtail speed to the speed limit for the road while allowing the driver to override the system (i.e. Voluntary ISA); or it can be linked to engine and brakes without the possibility of an override (i.e. Mandatory or Non-Overridable ISA).

The technology is of interest because of the known relationship between speed and risk of an accident and also because of the relationship between speed and injury severity in an accident.

The earlier External Vehicle Speed Control project demonstrated the viability of ISA technology. The follow up Intelligent Speed Adaptation project was commissioned to investigate how drivers would behave when using a Voluntary ISA in everyday car driving.

Important issues covered were how different types of driver (younger/older, male/female, habitual speeder/non-speeder) would be affected in terms of speed choice by use of the system, how their attitudes to the system would evolve over time, and whether they would revert to their pre-ISA speeding behaviour once the system was switched off.

Other work in the project has examined the feasibility of building a motorcycle with ISA and has investigated the impact of ISA on the operation of a truck used in a short-haul delivery operation. Finally the project has estimated the potential impact of ISA on future accidents, and has estimated the overall future benefit-to-cost ratios from ISA introduction.

Details of Field Operational Test

Start date and duration of FOT execution

Start: August 2003

Duration: 28 months (four separate trials of 6 months each)

Geographical Coverage

Trial 1: Leeds area with private motorists

Trial 2: Leeds area with fleet motorists

Trial 3: Leicestershire with private motorists

Trial 4: Leicestershire with fleet motorists

The Leeds trial was in a major urban area, although the speed limit data covered the whole of the Leeds Metropolitan District, which includes some outlying rural areas and villages. The Leicestershire area was mainly rural and small‐town.

Link with other related Field Operational Tests

It was quite similar in timing and scale to the French LAVIA project.


The main tasks of the Intelligent Speed Adaptation project were to:

  • Investigate how car drivers behaved when driving with ISA by means of set of field trials with a voluntary ISA
  • Study overtaking behaviour with ISA in a driving simulator
  • Prepare an ISA design for motorcycles and large trucks and to build a demonstrator of each
  • Investigate the costs and benefits of ISA


The car and truck trials demonstrated that ISA is now a mature technology which is capable of delivering substantial reductions in excessive speed and thereby considerable benefits in terms of safety. The behavioural results from the car trials show that the overridable ISA that was used by the participants reduced the amount of speeding among every category of user. It also affected driving on every road category, except the 60 mph (97km/h) rural roads, where there was comparatively little speeding by the participants in the pre‐ISA baseline.

Adapting ISA to a motorcycle environment was a more challenging proposition both in terms of the need to minimise weight and system volume and because of the requirement to consider the very different vehicle dynamics of a motorcycle. A demonstration ISA motorcycle was created that has offered a reliable, safe and effective vehicle for riding in user assessment trials within a test track environment. The response from riders was somewhat mixed.

Lessons learned

Main events


Summary, type of funding and budget


2.5 Mio EUR


Project Funded by the Transport Technology and Standards Division, Department for Transport (DfT), UK

Cooperation partners and contact persons

2: University of Leeds (School of Geography and Institute for Transport Studies) and MIRA Ltd.

  • Public Authorities:
  • Industry
    • Vehicle Manufacturer:
    • Supplier: MIRA Ltd
  • Users:
  • Universities: The University of Leeds
  • Research Institutes:
  • Others (specify):

Main Contact persons

   Professor Oliver Carsten
   Institute for Transport Studies
   University of Leeds
   +44 (0)113 343 5348
   Mr Mark Fowkes
   MIRA Ltd
   +44 (0)24 7635 5443

Applications and equipment

Applications tested

Intelligent Speed Adaptation

The position of the accelerator pedal demand (i.e. driver speed demand) was determined by an electronic sensor unit. The ISA control system compared this speed demand with the permitted maximum speed, i.e. the speed limit. Under ISA speed limiting, any demand by the driver for a speed in excess of the limit was ignored.

The driver could override this limiting either by pressing the red button on the steering wheel or by depressing the accelerator pedal fully so as to make contact with an actuator button. Speed limiting would be resumed when the driver brought vehicle speed back below the limit or when the driver pressed the reengage (opt‐in) button on the steering wheel or when the vehicle entered a new speed limit zone.

In addition to control by throttle, the ISA system could apply mild braking so as to try to keep the vehicle within the speed limit, for example when going downhill. This was done by means of an actuator fitted to the brake pedal. In order to discourage “over‐throttling” (i.e. the driver flooring the accelerator pedal), the ISA system would activate a vibrating motor fitted to the accelerator pedal in situations where the driver was depressing the accelerator excessively. This gave the driver tactile feedback and encouraged him or her to press less hard.

The speed limit map installed on one of the computers in the vehicle’s boot provided essential information for the ISA system to function correctly.


The ISA system was installed on a fleet of 20 Skoda Fabia Elegance 1.4 litre estate

One truck was used. It was a 7.5 tonne MAN TGL 180 rigid truck. (9 weeks of tests)

One motorcycle was used. It was a Suzuki Bandit 650S.

Equipment carried by test users



Test equipment

The system used two computers concealed below the rear floor of each vehicle. One of the two computers provided the information function, i.e. vehicle position and current speed limit, and the other provided speed limiting and data recording.


Pre-simulation / Piloting of the FOT

Method for the baseline

Phase 1 was one month with no ISA, to serve as the baseline,

Phase 2 was four months with the ISA system active,

Phase 3 was one month with the ISA once more inactive, for the study of carry‐over effects.

Techniques for measurement and data collection

Data was logged automatically and data collection was done remotely through a GSM link.

Collected data

Objective (logged data…):

In-vehicle data was collected at 10 Hz and logged automatically on a computer that could not be accessed by the user, and summary data was collected after each trip through a GSM (mobile phone) link. The data was subsequently imported into a relational database, where it could be linked to other data such as that on participant characteristics, participant attitudes and roadway data.

Following data processing and reduction, the final data file ready for analysis represents a total travel distance of 6,787 kilometres.

Subjective (questionnaires, focus groups…):

In order to determine changes in acceptability, attitudes towards the ISA system and workload experienced when driving with ISA, questionnaires were administered at four time points:

Time 1: at initial vehicle handover,

Time 2: following one month of ISA control,

Time 3: following four months of ISA control, and

Time 4: following a one-month return to non-ISA-controlled driving.

The Driver Behaviour Questionnaire (DBQ; Parker et al., 1995) was used to ascertain the frequency with which individuals committed various types of errors and violations when driving

Recruitment goals and methods

79 participants: 44 males and 35 females completed the four trials. Drivers were exposed for a period of 6 months.

Participants for the private field trials were recruited in response to adverts placed in local newspapers. Participants for the fleet trials were recruited from local organisations — in Leeds from employees of Leeds City Council (LCC), and in Leicestershire from various local authorities (including Leicestershire County Council, Leicester City Council, and Hinckley & Bosworth Borough Council) as well as a private company (Kingstone and Mutual Clothing Co).

Within each trial the aim was to balance the number of participants equally across various driver characteristics: male/female, young (25–40) or old (41–60), and intender/non‐intender (based on prior intention to speed as defined by an attitudinal questionnaire). It proved impossible to recruit the intended balance of driver across all the trials.

Methods for the liaison with the drivers during the FOT execution

Dedicated phone line.

Methods for data analysis, evaluation, synthesis and conclusions

Various, including analysis of vehicle behaviour (particularly speed), subjective data on attitudes and acceptance, observed drives along fixed routes, accident modelling and cost-benefit analysis.

Sources of information

Full Report: