Maryland's experience with all-electronic tolling after 14 months
2013-01-29: Before they opened the MD200 Inter County Connector (ICC), Maryland Transportation Authority (MdTA) had been handling 10,000 camera images a day at seven conventional toll facilities with their mix of transponder tolls and cash collection. That 4.8% was a mix of violations and transponder misreads - motorists in the transponder toll lanes sans a functioning transponder.
The cashless ICC with the mix of transponder tolls and camera tolls has more than tripled the image processing workload at the MdTA with an extra 21,000 daily.
The ICC is 18.8 miles long and for tolling purposes comprises five segments and five toll points per direction. Full length trips are therefore five reads and other trips vary between one and four reads per trip.
Tolls 14% image based, 86% E-ZPass transponder
Average weekdays they are doing 21,000 camera reads out of 151,000 total reads at the ICC, the difference of 130,000 reads being E-ZPass transponders in a 14% to 86% ratio. That 14% camera read rate on the new cashless facility compares to about a 4% average use of cameras to register violators or tag misreads at the seven facilities still collecting cash.
ICC camera based toll rates are 50% higher than transponder or tag tolls, so most regular users have the transponder.
The procedure is:
1. when no transponder is detected front and rear images are captured at each gantry
2. image review is performed to identify license plate numbers by automatic optical character recognition (OCR) or an operator viewing the image on their screen
3. trip construction by matching the license plates to determine the start and end of the trip to compute distance, then a toll rate is applied
4. if the license plate is registered to an account the trip is posted as an image toll to an E-ZPass account, if there is no account with that license plate then it is posted as a video toll
Parts of the ICC began tolling December 5, 2011 so they have about 14 months experience. At this point about half the images are processed by automatic OCR and about half get human review. They are slowly getting the percent of manual review down as the OCR data engine gets more verified images in its database.
Staff of six review images
The image review for the ICC is done by about six full time equivalent staff.
Obstructed or missing plates present the biggest loss they say. And around 1.5% of plates that are read produce no data or bad data on the name and address of the owner at the motor registries.
Maryland gets cooperation from 47 state motor registries. They also make use of R L Polk & Co and NLETS, National Law Enforcement Telecommunications System to get owner name and address.
Virtually all E-ZPass accounts of the 25 or so E-ZPass Group toll operators have the license plate number of the account holder.
Only small adjustments needed
They say both the hardware and the software of the toll system is working "as expected" and that only minor adjustments were required after the start-up. Toll system supplier was ACS, now Xerox.
The road runs east-west which makes for sunrise and sunset glare in peak hours but they say this has not been a problem with the cameras.
Complaints of mis-billing - "I wasn't even near the ICC that day…" - are "extremely low" they say with most complaints from customers who did not know the ICC is a toll road or got on the ICC by mistake.
A small number of complaints are due to long trips being split into two smaller trips, where the two smaller trip tolls total more than one long trip toll.
This can occur when a transponder is not read at the beginning or the end of a trip and the segment is recorded as a video toll or image toll trip.
The incidence of transactions being posted to an incorrect license plate is "almost non-existent." they claim.
They are collecting about 80% of the toll money due on image based tolls but hope to increase that over time.