How Many Engineers Does It Take to Count a Roundabout? UNIVERSITY OF MISSOURI-COLUMBIA
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Transcript of How Many Engineers Does It Take to Count a Roundabout? UNIVERSITY OF MISSOURI-COLUMBIA
How Many Engineers Does It Take to Count a Roundabout?
UNIVERSITY OF MISSOURI-COLUMBIA
Carlos Sun, Ph.D., P.E.
Introduction
Conservation equations
Hardware
Software/Algorithm
A Discussion of Automated Roundabout Counting:
Quick Bio• The road to traffic nerdom
– Start as electrical engineer in 1990• hardware/software
– Studied transportation engineering at UCI– ITS research at California PATH– 11 years teaching transportation, 8 at Mizzou
Roundabouts in the U.S.• Roundabout is one tool in a panoply of
solutions for intersections
• Modern roundabout: Las Vegas, 1990
• Increasing use, ~2000 as of January 2009 (RoundaboutsUSA)– 20k in France, 15k in Australia, 10k in the UK
• More and more roundabouts need to be counted and studied-> job security, yeah!
Magic Roundabout, Swindon, UK6 approaches/departures, 1 big and 5 kiddie roundabouts
Magic Roundabout:
Conservation Equations (FHWA): 4 Legged Roundabout
• 4x4=16 movements• 2x4=8 count
locations• Underspecified
problem
Conservation Equations: 4 Legged Roundabout
• But wait, if we neglect u-turns:– 12 movements– 12 counts: 8 entry/exit counts
+ 4 circulating
• Problem solved?
Gauss and Jordan say: Denied• Not linearly
independent– It’s still underspecified
• We need to count specifically: – right turns, or left turns,
or through movements– but at entry point, not
know which way a vehicle will end up!
1 0 0 0 0 0 0 0 0 0 0 -1
0 1 0 0 -1 0 0 1 0 0 -1 0
0 0 1 0 1 0 0 -1 0 0 1 1
0 0 0 1 1 0 0 -1 0 0 1 1
0 0 0 0 0 1 0 1 0 0 -1 -1
0 0 0 0 0 0 1 1 0 0 -1 -1
0 0 0 0 0 0 0 0 1 0 1 1
0 0 0 0 0 0 0 0 0 1 1 1
0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
Video Field of View• Apart from using cellular, bluetooth, or
other AVI-type tracking
• What are some achievable fields-of-view?
Count Estimation Systems, e.g. Eisenman and List
• Additional spec. w/Time stamps
• Count entrance, exits, circulating
• Assume FIFO
• Estimate turning movements
Other Estimation Procedures• Bi-Proportional: log-linear model (Van
Zuylen & Willumsen, Bell, Nihan & Davis, Hellinga)
• Algebraic Solution: rights turns (Robinson, Rodegerts et al.)
• Sequential Quadratic: constrained least squares (Cremer & Keller, Ashok, Dixon & Rilett)
• Factored Survey: surveys (Dixon)
Following Different Movements
• Differentiating b/t:– Circulating– Entering– Exiting
• Augment measured variables– Not longer
underspecified
• Problem w/tailgating
Common Tracking Algorithms (Coifman & Malik)
• Model-based – detailed geometric object models
• Region-based – connected region, “blob”
• Contour-based – reduce to boundary
• Feature-based – distinguishable pts., corners– Group rigid features moving together
Algorithm Step Examples
• Vehicle image capture• Background subtraction• Gradient/edge detection• Feature vectors• Inter vs. intra cluster movement
Multiple Cameras, e.g. Autoscope• Junction control • 8 cameras• 31 counting stations• 5000 vph• Krakow, Poland• No turning movements
necessarily
So how many engineers does it take to count a roundabout?
Assign a person to count each approach? (e.g. 4 persons for a 4-legged RA)
Have an engineer design an automated system
(e.g. HAL 9000)
Questions/Comments?FOR MORE INFORMATION
PLEASE CONTACT:
CARLOS SUN
UNIVERSITY OF MISSOURI
[email protected] of an Automated Solution for Deriving Roundabout
Turning Movements; Rescot, Sun; TRB 2008 Paper #08-0388
Automated Capturing of Roundabout Turning Movement Counts; 2008 National Roundabout Conference
http://www.teachamerica.com/RAB08/ListMenu.html