Appendix A

Trade-Off Comparison of Automated Technologies
Technology	Advantages	Disadvantages	Comment
Automatic Vehicle Identification Laser	Truck need only have bar code attached. Available laser technology used.	Weather and dirt can hinder read. Bar code and reader must be close to one another.	Reads bar code attached to truck. Laser scans as vehicle passes.
AVI Radio Frequency (RF) – tag	Although passive, some tags have "write" area permitting encoding of some info (entry point, date/time of entry)	Generally, tag data are fixed and unchangeable; can only be read. No processing capability. Cannot simultaneously read/send info.	Transponder tag in/on vehicle. Read by RF reader or antenna. May either transmit (tag contains transmitter and generates RF signal); or receive (tag reacts to received RF from antenna; lacks transmitter)
AVI Radio Frequency (RF) – smart tag	Can send/receive at same time. Actively generate signal that communicates with antenna/receiver	Cannot update customer/vehicle information	On-vehicle, used in conjunction with "in-lane" RF antenna/reader. Communicates: vehicle/customer info, account balance to toll system. Vehicle/customer data fixed; other tag info updatable (e.g., account status). Contains microprocessor which updates with tag usage.
AVI Radio Frequency (RF) – smart card w/ RF transponder	Generates its own signal. Can operate in either full or half duplex communication mode (i.e., either send-receive simultaneously or send or receive). Can receive and encode updated info on card. Proven technology, low cost	Requires both smart card and separate RF transponder (tag) in-vehicle. Requires infrastructure investment and carrier purchase of card, transponder. Requires cross-border operational agreement.	Integrated circuit. Contains microprocessor, memory. Stores account balance. RF transponder located in-vehicle; transponder interfaces with smart card, permits communication with antenna/receiver on card info, vehicle info. Used at LAREDO World Trade Bridge to collect 95% outbound truck data; also provides WIM data to roadside sensor.
AVI Infrared (IR) – IR tag	Proven technology, relatively low cost	Read-only. No processing capability.	Relies on IR frequency, rather than RF, for communication. In-vehicle tag, read by reader/transmitter in toll lane. Used with in-lane IR antenna that provides vehicle, customer info to toll system.
AVI Infrared (IR) – Smart card w/ IR tag	Generates own signal. Provides for communication to/from antenna/receiver. Can receive, encode updated info on card	Infrastructure costs. Environmental interference a possibility. Requires cross-border operational agreement	Relies on IR frequency, rather than RF, for communication. Same as RF transponder and smart card.
Enhanced Common Inductive Loop	Provides indication of vehicle presence, count, and occupancy. Paired, can measure speed. Older technology; in use. Updated versions demonstrate ability to measure travel time. Relatively inexpensive purchase and installation costs. Some updated versions can identify a vehicle "signature"; inductive signature analysis can classify vehicle as to truck or car.	Generally does not differentiate size or type of vehicle. Time and difficulty of wire installation. Environment can affect inductance reading. Vehicle position also affects reading if offset or changing lanes while crossing. When crossing vehicles similar (e.g., all CMVs), differentiation among them difficult.	Generally hex-shaped wires, buried in road. Vehicle passage causes fluctuations in detector's electrical inductance. California PATH researching. Its upgraded protocols and software, using detector card, apparently permit vehicle matching as vehicle moves through processing, improving local count & vehicle classification accuracy. Two different systems developed.
Enhanced Loop-Based Traffic Surveillance (Signature Inductive Sensors)	Uniform data across lanes of traffic, despite lateral offset/turning vehicles. Faster installation; more defined signal data. Ideal: better discrimination among vehicles.	Similar to above.	Covers roadway, edge to edge.
Mobile Phone Locating	No new infrastructure required. Can track vehicle location. Later versions don't require line-of-sight triangulation of signal. Latest technology permits continual updating of data from multiple callers along a roadway to identify speed. Permits historic analysis of speed data from stored inputs, as well as "real-time" display of traffic flow. Needs only one cell site rather than multiple towers in rural locales, such as borders.	Requires RF direction finding, infrastructure (multiple towers) in basic technology. Depends upon callers making sufficient calls; on border, must be enough made between monitoring points to provide significant time and delay data. Current origin/destination geolocation capability from mobile phone not as accurate as on-site sensors [is this problem if sampling?]	CAPITAL ops test, Washington, D.C. 1994. Capital Wireless Integrated Network (CapWIN) followed, demonstrating potential of phone monitoring. CapWIN spin-off technology may simplify location issue. Employs (1) measuring distinct RF patterns from caller's phone and (2) evaluating multi-path characteristics of radio signals arriving at cell site from caller (i.e., via buildings, other obstructions off which signal bounces). Would alleviate need for line-of-sight to determine location of call. Related new technology takes mobile phone data from multiple wireless carriers, links with other ITS and GIS data, determining: average vehicle speed; real-time traffic patterns, & velocity data as means to determine roadway conditions.
License Plate Readers	Already in use along northern and southern borders by Customs for automobile review. Millisecond identification of suspect car. High positive identification rate alleged. Portable version available.	Not now available for truck monitoring. For border monitoring, existing reader locations at border crossing may not satisfy sampling requirements of this border reviews. Slow-moving or turning vehicle causes misreading. Portable unit not as accurate. Trucks may confuse reader with multiple plates, or damaged/dirty ones. Placement of unit for truck monitoring may be more difficult than for cars. Units vulnerable to theft, so security an issue. Cost high for travel time evaluation.	LPRs electronically read automobile's front, rear plates; provide input to Customs in digital format. Used by Customs to check for stolen cars, criminal usage. Initial use by Customs: vehicle entering from Mexico. Future: both directions.
Vehicle Matching System	Allegedly high probability of vehicle identification. Portable version available.	Would provide "downward" view of commercial vehicle. Expensive for travel time evaluation.	Trailer employs "arm" with sensing technology over 2 lanes of traffic. Compares image patterns of individual vehicle, "fingerprinting" w/ time, date, position stamp. These communicated to exit system, which stores and compares to vehicle as exits. Now used for speeding verification. License plate reader used to document offense. Allegedly can work with any kind of license plate. Relies upon laser to detect vehicles, which activates camera that captures video image.