From computing the ideal trajectory to applying it while driving

Collaborative research between LTE, LESCOT, LEPSIS and the Ampère laboratory in Lyon ², was conducted with the primary goal of quantifying the savings resulting from eco-driving for vehicles of different types  (conventional, electric or hybrid). This involved the use of digital optimisation techniques. After this, an eco-driving tool based on this optimisation was designed and tested for a conventional vehicle. The design process took account of the various constraints that may be present. The device thus took account of traffic conditions and pollutant emissions and the receptiveness of drivers and their ability to assimilate the information they receive.

Moreover, taking account of traffic constraints has shown that the potential savings resulting from eco-driving diminish as traffic becomes more congested, even if it still remains a way of appreciably reducing vehicle consumption. The inclusion of emissions constraints has led the researchers to conclude that eco-driving provides the same emissions levels as normal driving and can reduce them in the absence of journey time constraints³.

The eco-driving aid system communicates with the driver via two screens. The screen on the left is integrated with the vehicle’s speedometer and continuously displays a recommended range of speeds, except in risky situations. The screen on the right provides non-real-time advice (after a sequence of driving actions) and serves an educational purpose (the rights belong to IFSTTAR - LTE and LESCOT).

Finally, optimisation algorithms were integrated within the effective and secure assistance system by using a driving simulator. Twenty individuals were recruited to take part in the evaluation of the system as drivers with and without the aid system. The results showed that an optimised eco-driving system that displays simple information can be both effective and relatively well accepted by drivers. The average reduction in fuel consumption during the experiment was approximately 11%.

Eco-SiVIC, an eco-driving and 3D immersion platform  

Other research has been carried out on a platform known as pro-SiVIC (Virtual Vehicle, Infrastructure and Sensor Simulator) developed by the LIVIC. This platform is mainly used for modelling sensors and prototyping driving aids. In more concrete terms, it enables us to simulate the operation of sensors that are installed in vehicles (such as video cameras, RADAR systems, laser telemetry, GPS devices, etc.). The result of these simulations is then used to develop driving aids that use the sensors in question. In this context, a consumption sensor for heat engines has been implemented, making eco-driving projects possible.

In the last few years work has been conducted to extend this platform to allow participants to drive it. This involved providing an interface for the platform with driver controls (steering wheel and pedals) and computing and displaying stereoscopic images ⁴ with a virtual reality headset, thereby providing full 3-D immersion.

A virtual reality headset that displays 3D images and measures head movements (on left) and an example of stereoscopic images [2] with speed and fuel consumption displays (on right) (rights LIVIC IFSTTAR).

This platform, which is fitted with driver controls, was presented to the public during the “Fêtes de la science” and the 2014 Paris motor show ⁵. In this context, the drivers’ aim was to travel as far as possible with a small amount of fuel (0.15 liters). The participants were given a score based on the distance covered, showing them whether or not they had complied with the rules of eco-driving.

On the scientific level, the aim of this platform is to be able to quantify the impact of driving on consumption in specific situations such as crossing an intersection. In addition, the research team is considering quantifying how certain vehicle parameters affect consumption. Possible parameters include the vehicle’s capacity to accelerate and brake, or how well the tyres grip the roadway. Future research will aim to extend these studies to hybrid technologies.

The value of simulation tools for eco-driving

This work, which has been carried out in several of IFSTTAR’s laboratories, has shown that installing consumption evaluation devices on driving simulators can open the way for various research projects which would be difficult to implement in real situations. The first results indicate that eco-driving aids have a beneficial effect.

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¹ A definition of eco-driving can be found, for example, in the following: Barth, M., & Boriboonsomsin, K. (2009). Energy and emissions impacts of a freeway-based dynamic eco-driving system. Transportation Research Part D, 14, 400-410.

² As part of the PhD thesis of Félicitas Mensing, defended in 2013: “Optimal energy utilization in conventional, electric and hybrid vehicles and its application to eco-driving”.

³ The detailed results are presented in: Mensinng, F., Bideaux, E., Trigui, R., Ribet, J., & Jeanneret, B. (2014). Eco-driving: An economic or ecologic driving style? Transportation Research Part C, 38, 110-121.

⁴ Stereoscopic images make it possible to see the scene in 3D. On of the images corresponds to what is seen by the left eye and the other, which is slightly different, corresponds to what is seen by the right eye. The slight differences between the two give an impression of image depth.

⁵ The eco-SiVIC platform is now presented by CIVITEC (a subsidiary of the ESI group) and a licencing agreement to enable them to exploit the system is due to be signed with this firm in 2016.