Speed and Acceleration Characteristics at Metered On-ramps

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1 Speed and Acceleration Characteristics at Metered On-ramps GUANGCHUAN YANG Graduate Research Assistant Reno, NV89557 September 11,

2 2 Presentation Overview Background Data Collection Data Extraction Procedure Data Analysis Major Findings

3 3 Problem Statement Metered On-ramp Downstream Acceleration Distance Upstream Queue Storage Space

4 4 Problem Statement Tradeoff between acceleration length and queue storage space

5 5 Problem Statement Tradeoff between acceleration length and queue storage space

6 6 Problem Statement Tradeoff between acceleration length and queue storage space Proper ramp meter location

7 7 Field Cases Hazel Blvd/WB 50, Sacramento, CA 12th Ave/NB 99, Sacramento, CA

8 8 Speed and Acceleration Measurement Objectives Develop distance versus speed relationship for design Explore distance versus acceleration profiles Current Issues Out of dated data Un-realistic assumptions Challenge Measurement error

9 9 Previous Studies Common Acceleration Models (a) Constant model (b) Dual-regime model (c) Linear decreasing model (d) Polynomial model

10 10 Previous Studies Caltrans s Probe Vehicle Testing (Oto, 1988) Average Acceleration Rate: 5.47 ft/s 2 a ft. 1 3 a ft.

11 11 Previous Studies Rakha s Vehicle Dynamic Model (Rakha 2002, 2004) (a) speed versus time, (b) acceleration versus time, (b) (c) speed versus distance, (d) acceleration versus distance

12 12 Pilot Data Collection Camera view on 40 feet mast

13 13 Pilot Data Collection Parallel cameras with view overlapping

14 14 Pilot Data Collection Probe vehicle equipped with GPS trajectory recorder

15 15 Pilot Data Collection Camera view from un-manned drone at 150 ft.

16 16 Pilot Data Collection Magnetic traffic counter

17 17 Pilot Data Collection Parallel cameras with stopwatch synchronize the time

18 18 Field Data Collection

19 19 Field Data Collection Cone layout (Industrial Pkwy/NB ALA 880)

20 20 Data Extraction Procedure t1 t2 t3 a (t1~t2) a (t2~t3) S1 S2 S3 T 1 2 T 1 2 T 2 2 T 2 2 T 3 2 T 3 2 T1 T2 T3 V1 V2 V3 v 0 v S1 v S1+S2 v S1+S2+S3 a (0~S1) a (S1~S2) a (S2~S3)

21 21 Example of An Individual Sample

22 22 Example of An Individual Sample

23 23 Speed versus Distance Profile Site: Fruitridge Rd/NB 99, Caltrans District 3

24 24 Acceleration Length Design Recommendation

25 25 Average Acceleration vs. Distance Profile Site: Fruitridge Rd/NB 99, Caltrans District 3

26 26 Taper vs. Parallel Sites: Bradshow Rd/WB 50 & Fruitridge Rd/NB 99, Caltrans District 3

27 27 Passenger Car vs. Truck Site: Industrial Pkwy/NB 880, Caltrans District 4

28 28 Three Stage Acceleration Behavior Site: Douglas Blvd/WB I-80, Caltrans District 3

29 29 Three Stage Acceleration Behavior 530 ft. Stage 1 Stage 2 Stage 3

30 30 Three Stage Acceleration Behavior Site: Industrial Pkwy/NB ALA 880, Caltrans District 4

31 31 Three Stage Acceleration Behavior Stage 3 Stage 2 Stage ft.

32 32 Major Findings Passenger cars can usually accelerate from 0 mph to mph in approximately 500 feet Vehicles usually accelerate at a higher acceleration rate when the speed is lower and vice versa A taper merging type ramp seems likely to generate higher acceleration rates compared with a parallel merging type ramp A three stage acceleration behavior was observed at typical ramp metering sites in both Caltrans District 3 and District 4 The current used AASHTO acceleration lane length design standard seems to be too conservative for the modern vehicles

33 33 Acknowledgement This research is sponsored by California Department of Transportation (Caltrans). The presenter appreciate greatly for Laura, Dean, Rasool, Arafat, Daniel, Brian, Don from UNR CATER, and Larry Hall, Leo Anselmo from Caltrans District 3 for their consistent help with the device testing and field data collection.

34 34 References 1. Loutzenheiser, D. W., B. D. Greenshields, and J. A. Buchanan. Speed-Change Rates of Passenger Vehicles. Proceedings of 18th Annual Meeting, Highway Research Board, Washington, D.C., 1938, pp Bham, G. H., and R. F. Benekohal. Acceleration Behavior of Drivers in a Platoon. Proc., First International Driving Symposium on Human Factors in Driver Assessment, Training and Vehicle Design, University of Iowa Public Policy Center, Iowa City, 2001, pp Long, G. Acceleration characteristics of starting vehicles. Transportation Research Record, No. 1737, TRB, National Research Council, Washington, D.C., 2000, pp Akçelik, R., and D. C. Biggs. Acceleration Profile Models for Vehicles in Road Traffic. Transportation Science, Vol. 21, No. 1, Wang, J., K. Dixon, H. Li, J. Ogle. Normal acceleration behavior of passenger vehicles starting from rest at all way stop controlled intersections. Transportation Research Record: Journal of the Transportation Research Board, No. 1883, TRB, National Research Council, Washington, D.C., 2004, pp Oto, R. Vehicle acceleration tests. Memorandum issued on March 9, District 4, California Department of Transportation, Oakland, California. 7. Rakha, H., M. Snare, and F. Dion. Vehicle Dynamic Model for Estimating Maximum Light-Duty Vehicle Acceleration Levels. Transportation Research Record, No. 1883, TRB, National Research Council, Washington, D.C., 2004, pp Rakha, H., and I. Lucic. Variable Power Vehicle Dynamics Model for Estimating Maximum Truck Acceleration Levels. Journal of Transportation Engineering, Vol. 128, No. 5, 2002, pp

35 35 Questions and Discussions Guangchuan Yang UNR CATER