Bicycle Detection Using Caltrans Type D Loops: More Options for Practitioners Presented to ITE District 6 Annual Meeting June 24-27, 2012 by John Kerenyi, P.E., Senior Engineer, City of Moreno Valley

Summary of Presentation California AB1581 Caltrans recommendations Desired configurations/deviation from Caltrans recommendations ILD theory of operation Type D loop field measurements Calculations/recommendations

California AB1581 At new or substantially modified intersections (>50% of detection replaced), re: detection: To the extent feasible and in conformance with professional traffic engineering practice, to be installed and maintained so as to detect lawful bicycle or motorcycle traffic on the roadway. AB1581 became effective in 2010

Caltrans GuidanceRequirements Reference rider described – –4 ft tall – –90 lbs min – –16 aluminum wheels, non-ferromagnetic frame Reference rider described in a manner suitable for testing detection by many means e.g. ILD, video, microwave Either detect reference rider, or place approach on recall (semiactuated/pretimed operation allowed) Bike pushbuttons not enough anymore Bike min green timing recommended

Caltrans Type D Loop

Type D Loop Variations City of Moreno Valley City of Los Angeles

Caltrans Type D Loop Recommendations Wire in series with three other standard (e.g. round or octagonal) loops which are connected in parallel to each other Wire in series with two other standard loops Wire to own detector card channel Detector Card D E E D EE E D

Desired Configurations E D E D E D E D EE Case 1: Two loops in one lane Case 3: Four loops in two lanes Case 2: Four loops in one lane

ILD Theory of Operation

Sensitivity

Series or parallel? E D Parallel wiringSeries wiring D Detector Card E D E Seek to minimize L D = 190 μH L E = 60 μH (Three Turns) (Five Turns) S circuit = 0.76 S D S circuit = 0.24 S D Sensitivity factor Case 1

Case 2 E D EE Parallel wiringSeries wiring Maximize Minimize S D minimized by placing the Type E loops in series S D minimized by placing the Type E loops in parallel E E E D Detector Card D E E E SF: 0.61 (4 turns) SF: 0.51 (3 turns)

Case 3 E D E D E DD Detector Card EE D E E DD E D E D E D Configuration 1Configuration 2 Configuration 3Configuration 4 SF: 0.33SF: 0.17 SF: 0.26SF: 0.17

Discrimination of Bicycles and Vehicles Desirable to avoid timing long minimum greens every cycle for occasional bicyclesDesirable to avoid timing long minimum greens every cycle for occasional bicycles Known effortsKnown efforts –OCTEC ILD method –Microwave: Intersector, others –Video detection manufacturers

Recommendations Case 1 (two loops): Parallel Case 2 (one D and three E): Parallel/series (opposite of Caltrans recommendation) Case 3 Further research is necessary esp. for splashover D Detector Card E EEE D E DD E