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General information
Type: Field operational test
Tested system/service: Intelligent Speed Adaptation
Countries: Denmark 24 test users
1 partners 24 vehicles
Active from 1999/08/01 to 2002
Harry Lahrmann
Aalborg University
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The project has developed an OBU with an informative ISA-system (hardware and software). The system works in this way: a GPS-receiver establishes the position of the car one time each second. A map matching program locates the position on a digital road map which includes speed limits. A display shows the local speed limit, and the local speed limit is compared with the speed of the car. If the speed measured by the odometer exceeds the speed limit by more than 5 kph, the system responds by a friendly female voice which for example says “50, you are driving too fast”. At the same time the display flashes, and a red LED lights up. The voice is repeated every 6 seconds if the speed limit continues to be exceeded by more than 5 kph.

The system has been tested by 24 test drivers. The test shows larges variation in the effect on the drivers’ speed, most of them reduced their speed: some had large reductions; other had small reductions, while two slightly increased their speed. On average the test drivers reduced their speed violation from 9 - 13 km/h to 4-7 km/h, i.e. a speed reduction of 5 – 6 km/h. Only two test drivers which violated the speed limits on a regularly basis in the before period did not reduce their speed with ISA in the car, and one of these two drivers believe that he would reduce his speed by using the system for a longer period. The test-driving has also increased the test drivers’ awareness about the existing speed limits.

Details of Field Operational Test

Start date and duration of FOT execution

6 weeks with Start: 1 March 2001

Geographical Coverage

Municipality of Aalborg, 1200 km roads

Link with other related Field Operational Tests


The project has two purposes:

A: to develop an On Board Unit (hardware and software) for a GPS-based ISA-system,

B: to have the On Board Unit (OBU) tested by test drivers in order to obtain user reactions to the system and to measure how the system influences the test drivers choice of speed.


The 85% quantile for speed violations show a clear decline - in average 5 – 6 kph. At the same time, the analyses show a clearly larger decline in the speed violations in the rural areas than in the urban areas. However, the test drivers are still violating the speed limit, but the violations are reduced from 9 – 13 kph to 4 – 7 kph.

The experience of the test drivers is that the system is highly credible, i.e. the system rarely displays a wrong speed limit. Many of the test drivers are aware that the concept “freedom” in relation to speed is about the “freedom to break the law”, and the test drivers don’t feel that ISA has limited their freedom. However many of them feel annoyed when they are busy, and all type of test drivers have ignored the system in such situations. The majority of test drivers believe that lower speed generally doesn’t lead to a significant higher travel time. However in situations where they are busy, many of them respond by increasing speed.

Lessons learned

Main events


Summary, type of funding and budget

0.5 Mio EUR of public funding

Cooperation partners and contact persons

  • Universities: Aalborg University

Main Contact person

Harry Lahrmann
Associate Professor and project manager in the FOT
Traffic Research Group
Department of Development and Planning
Aalborg University
Fibigerstraede 11
9220 Aalborg Oest

Phone +45 9635 8381
Mobile: +45 4056 0375

Applications and equipment

Applications tested

Informative ISA


24 cars

Private cars with after market systems

Equipment carried by test users


Test equipment



Pre-simulation / Piloting of the FOT

Method for the baseline

Two weeks baseline – four weeks testdrive

Techniques for measurement and data collection

Collected data

0.5 million raw logged every second, storing on a flash memory

3 questionnaires with test drivers

1 focus group interview

In the project we have logged the participants driving every second and we collected 500,000 raw with log data. We are interested in corporation with other ISA research project in doing comparative studies.

Interested are welcome to contact us

Recruitment goals and methods

volunteer found by advertising in the local newspaper

Methods for the liaison with the drivers during the FOT execution

Hotline telephone

Methods for data analysis, evaluation, synthesis and conclusions

Logdata analysis in excel, Matlab and ArcGis

Questionnaires and focus group

Sources of information