Road friction monitoring in intelligent traffic system

Transcription

1 Road friction monitoring in intelligent traffic system Workshop, Best Practices on Deployment of Monitoring Technologies and Services, VTT, Espoo, Finland Pasi Pyykönen, Jukka Laitinen, Pekka Eloranta, Tomi Korhonen VTT Technical Research Centre of Finland

2 2 Background Slippery roads and especially motorway ramps causes several accidents each year One reason to accidents is difficulty to evaluate correctly the road friction i.e. due to different road surface materials on ramps. Static road side units measure friction and road condition only in one location.

3 3 Background By using monitoring system as well in moving vehicles we can make more precise measurements where installing static road side station is not profitable. Sensor information to driver from traffic environment is limited to car sensors although new mobile phones and navigators are capable to receive information almost in real time. In addition new communication technologies like IEEE p standard for vehicle to vehicle to communication is available. Our intelligent traffic system shows possibilities to merge data from road side units and vehicles and provide it to end users in feasible format.

4 4 System overview Intelligent traffic system In our intelligent traffic system, all measurements are stored through 3G/4G connection in to database where data can be viewed in using several parameters i.e. time and measurement values. Intelligent traffic system is divided to four different modules which communicate through database or V2X communication. In addition road side unit allows direct access to measurements and video image through HMTL5 interface. Database enables providing map interface for mobile devices.

5 5 System overview Road side unit The road side unit (RSU) takes images from road section with stereo camera and calculates road weather type. Installed on the motorway ramp to monitor road section on end of the ramp. From lookup table, system estimates road friction based on measurements. RSU unit sends measurements to vehicles through V2X communication using CAM/DEMN messages and to database using 3G mobile connections

6 6 System overview Vehicle Vehicles can collect data with variable sensors. Measure air and road surface temperature, ABS/ESP status, 3Daccelerations and status of dashboard controls. IcOR road friction detection system Vehicles can communicate through V2X communication using CAM/DEMN with RSUs and other vehicles nearby. In addition, vehicles communicate with database using mobile 3G connections.

7 7 Database is used to store all measurements from vehicles and road side units. System overview Database In intelligent traffic system database contains weather information from environmental sensors with data from vehicle sensors. It is possible to extend the database contain more accurate information from i.e. traffic flow for emission calculation.

8 8 The IoT ITS Pilot uses and provides user interface for nomadic devices i.e. smartphones which penetration is expected to increase in near future. System overview Mobile interface This will expand cooperative systems to cover users more specifically, instead of just the vehicles and the infrastructure.

9 9 Friction monitoring system (IcOR) was installed in road side unit. Implementation and result Friction monitoring The monitoring system can calculate parameters of road surface with stereo camera equipped with polarization filters. The friction monitoring system acquires images from the stereo camera and executes analysis. Monitored road surface is 30 meters from the camera Using these parameters, system estimates road friction from lookup table for friction values.

10 10 Implementation and result Tampere IoT ITS Pilot IoT ITS pilot system was installed on the motorway ramp of Tampere. Area was chosen because of demanding road surface conditions during winter time Vehicle driver is difficult to estimate slippery and proper speed when entering to ramp. Intelligent traffic system can warn the driver to lower speed if needed. IoT Pilot area is covered also with 3G/4G mobile network to provide communication RSU units with p communication.

11 11 V2V/V2I communication is implemented using IEEE p communication. Implementation and result Tampere IoT ITS Pilot Vehicles or road side units can send CAM/DENM messages other units/vehicles nearby. One message can contain GNSS position of sender, message type and message. In intelligent traffic system, message contains weather warnings with measurement position and friction measurement.

12 12 Implementation and result Tampere IoT ITS Pilot In addition to I2V message, road side units and vehicles communicate through database. : Vehicle : RSU : Server : Karttarajapinta Vehicle or road side unit can send SOAPmessage to server including collected measurements. 1 : SOAP() 2 : SOAP() : User Every measurement includes timestamp and location from GPS-receiver. 3 : SOAP() Measurements are visualized on server side providing HTML5 implementation for mobile devices or PC browsers. 4 : HTML5()

13 13 Implementation and result Tampere IoT ITS Pilot

14 14 Tampere IoT ITS Pilot shows that existing sensor implementations can be easily connected to one data gathering system. Best practices Tampere IoT ITS Pilot This implementation allows easy way to connect sensors to this system if communication follows current implementation. Best practice is allow to use well known communication interfaces and channels to exchange information between different sensor implementations.

15 15 Best practices Sensor and communication implementation The IcOR friction estimation could be further improved by implementing more intelligent calculation using information from temperature or humidity sensor. Best practice is to increase sensor reliability with other supporting sensors. In future database will be used to collect friction data and raw measurements from vehicles and other RSUs than were used in this pilot. Best practice is to exploit database for provide data for web services. This will help developers collect and compare information from different sensor units. Best practice is to design traffic system to provide easy access to developers and i.e. road authorities. Mobile user interface could be further improved by implementing warning system if i.e. vehicle is approaching ramp with low friction value. Best practice is to find easy way to provide RSU data to road users. One way to approach is to use HTML5 interface that allows easy mobile access without software installation.

16 16 Contact Pasi Pyykönen VTT TECHNICAL RESEARCH CENTER OF FINLAND Tekniikankatu 1, Tampere, P.O. Box 1300, FI Tampere, Finland phone fax Jukka Laitinen VTT TECHNICAL RESEARCH CENTER OF FINLAND Tekniikankatu 1, Tampere, PL 1300, Postinumero Puh , faksi

17 17 Thank you very much for your attention.

18 18 VTT - 70 years of technology for business and society