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Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion

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Since many years, as a consequence of fossil fuels rarefaction and climate changes, ecology has become a major challenge of our society. In this field, many improvements could be realized on the transportation side and more precisely on passenger cars which are an important source of pollution. A quick and efficient solution to reduce fuel consumption and so, greenhouse gases emissions, is to adopt an ecological way of driving, called ecodriving.
However, is ecodriving really efficient in terms of mobility and environment at a global point of view? The benefits of ecodriving have often been studied for an isolated vehicle and rarely for a whole network. The aim of this work is to estimate the effects of ecodriving on traffic congestion and fuel consumption according to the percentage of ecodrivers in the population. This has been achieved using a class of ecodriven vehicles with a car-following model (Intelligent Driver Model) and with a transport simulation software (Aimsun). Results show that the effect of ecodriving on the traffic congestion and pollution is not linearly linked to the proportion of ecodrivers and this effect varies according to the driving conditions. In some cases, ecodriving is cons-productive and fuel consumption increases. Future works will concentrate on experimental validation, on modeling the effect of ecodriving on road safety and on improving the different models.

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Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion

  1. 1. Young Researchers Seminar 2011 DTU, Denmark, June 8 - 10, 2011 Young Researchers Seminar 2011 DTU, Denmark, 8 - 10, 2011 Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion ORFILA Olivier IFSTTAR
  2. 2. 2 Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion
  3. 3. 3 What is ecodriving ? • No clear and objective definition exists • Example: “Ecodriving is a way of driving that reduces fuel consumption, greenhouse gas emissions and accident rates” (www.ecodrive.org) Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion
  4. 4. 4 Ecodriving definition Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion Using driving rules (Saboohi 2009, Walhberg 2007, Zarcadoula 2007) • do not drive too fast, • maintain steady speeds, • do not accelerate too quickly, • anticipate traffic flow when accelerating and slowing down, • shift gears sooner to keep engine speed lower, • keep the vehicle in good maintenance.
  5. 5. 5 Ecodriving Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion • In the literature, the benefits of ecodriving are studied for the subject vehicle only. • Hypothesis 1: ecodriving has an impact on the traffic level and on the fuel consumption on the global network • Hypothesis 2: this impact depends on the penetration rate of ecodriving.
  6. 6. 6 Aims of this study Title of the presentation Evaluate the impact of ecodriving on fuel consumption and traffic congestion: • On a whole network • According to the ecodriving penetration rate • For different road types and traffic demands
  7. 7. 7 Light duty vehicles and driver Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion
  8. 8. 8 And the role of passenger cars ? • Fuel consumption US 2004 (IEA) • In France, Light Duty Vehicles represents 55% of greenhouse gas emissions (source: ministry of sustainable development) Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion
  9. 9. 9 And the role of vehicle, infrastructure and driver? Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion Driver: •Desired acceleration •Desired speed •Engine speed,… = ecodriving Vehicle: •Mass •Engine •Tires,… Infrastructure: •Geometry •Pavement texture
  10. 10. 10 Methodology: an ecodriving modelling Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion Ecodriving parameters Ecodriven vehicles Normally driven vehicles Traffic demand Road network Traffic micro simulation Fuel consumption Traffic indicator (mean speed) % •IDM (Intelligent Driver Model) Treiber, 2000 •Gipps model 1981 (AIMSUN) •Interurban •Urban •Free traffic state •Intermediate traffic state •Congested traffic state 2 types of roads x 3 traffic states x 11 proportions of ecodrivers x 10 replications = 660 numerical tries
  11. 11. 11 Traffic and fuel consumption Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion
  12. 12. 12 Traffic micro simulation on interurban roads • Intelligent Driver Model (Treiber, 2000) : Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion Desired acceleration Desired speed Distance between vehicles b: desired deceleration Speed difference Desired time headway Minimum gap Model parameter=4
  13. 13. 13 Fuel consumption on interurban roads • Energy consumed • Corrected with an efficiency ratio (Wang, 2008) Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion
  14. 14. 14 Traffic micro simulation on urban roads • Gipps model (Gipps, 1981) with Aimsun (TSS) Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion 0% 50% 100% Free Intermediate Congested
  15. 15. 15 Fuel consumption on urban roads • Aimsun and Alçelik model (Alçelik, 1982): ▫ 4 states are defined:  Idling  Cruising  Accelerating  Decelerating ▫ 7 parameters from the vehicle are required Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion
  16. 16. 16 Interurban roads Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion
  17. 17. 17 Results : interurban road – free traffic • Fuel consumption ▫ Slight and steady decrease ▫ Fuel consumption reduces by 7.7% • Traffic indicator ▫ Slight decrease (9.1%) ▫ 2 minutes lost on a 20 minutes travel Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion Optimal proportion of ecodrivers : 100%
  18. 18. 18 Results : interurban road – intermediate traffic • Fuel consumption ▫ Non linear variation ▫ From 0 to 20% of ecodrivers : -8.5% ▫ From 0 to 100% : +2.4 % • Traffic indicator ▫ Sharp decrease : -38% Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion Optimal proportion of ecodrivers : 20%
  19. 19. 19 Results : interurban road – congested traffic • Fuel consumption : ▫ Strong reduction : -35.8% • Traffic indicator ▫ Sharp decrease : -55% Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion Optimal proportion of ecodrivers : 30%
  20. 20. 20 Urban roads Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion
  21. 21. 21 Results : urban road – free traffic • Fuel consumption ▫ Slow decrease : -9.8 % • Traffic indicator ▫ Strong decrease : -19.7% Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion Optimal proportion of ecodrivers : not defined
  22. 22. 22 Results : urban road – intermediate traffic • Fuel consumption ▫ Non linear variations : -7.6% • Traffic indicator ▫ Non linear variations : -32.3% Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion Optimal proportion of ecodrivers : not defined but 80% should be avoided
  23. 23. 23 Results : urban road – congested traffic • Fuel consumption ▫ Strong effect: -19.6% • Traffic indicator ▫ Nearly steady Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion Optimal proportion of ecodrivers : 100%
  24. 24. 24 Proposed solutions for ecodriving • Short term: promote ecodriving on identified situations • Middle term: giving real time advice to the driver • Long term: develop a strategy to manage a whole network Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion
  25. 25. 25 Theoretical and practical implications • Innovative method to analyze ecodriving. • It can be applied for several existing or future assistance systems • Recommandations on ecodriving Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion
  26. 26. 26 Conclusions and perspectives Conclusions Study drawbacks • Ecodriving is efficient at a global point of view • In some situations, the fuel consumption increases with the % of ecodrivers • The optimal proportion of ecodrivers varies with the situation • Current proportion of ecodrivers is unknown • The engine speed has not been taken into account Impact of the penetration rate of ecodriving on fuel consumption and traffic congestion Perspectives • Refine the modelling • Experimental validation

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