Posts Tagged ‘AVL’
Wednesday, August 26th, 2009
Many articles have been written about the advantages of AVL systems in fixed route transit agencies. While AVL does come with a host of benefits, including predicting next bus arrival times, lofty claims about a rider walking out their door 30 seconds before the arrival of their bus simply isn’t the case in most cities. Agencies salivate at the thought of people knowing exactly when their bus is going to arrive, but it’s important to realize that once implemented, AVL delivers predictions and not guaranteed arrival times.
The big question is why? Riders may wonder why, with all the GPS hardware and software, they can’t know exactly where their bus is every second of the day. And, why their PDA says the next bus will be at the stop in two minutes, yet they’re still standing there two minutes after the fact.
To answer this it’s important to understand how arrival predictions are constructed. First and foremost, while a vehicle may know where it is at every given second, it can’t ‘send back’ its location to in-office and online software systems every second. Not only would this incur huge costs (due to the volume of data being constantly sent), but data providers simply don’t allow it (as it would clog up their entire data network). As a result, software packages have to make an educated guess as to where a vehicle is based on the location information it does receive. Typically, vehicle location reports are sent every one to three minutes. If we assume an average vehicle speed of 12 miles/hour, this translates to anywhere from 0.2 to 0.6 miles of distance covered by the vehicle between location reports. That’s 0.2 to 0.6 miles during which the software has to ‘guess’ the vehicle’s location.
In most cases, software applications are able to predict arrival times based on a number of pieces of information:
• Last location received and speed of the vehicle
• Historical traffic and speed information for a given road section
• Distance from the target
• Current traffic information
All of this information does aid in arrival predictions, however, it will never be able to exactly predict an arrival time. Road conditions may vary from calculated values due to accidents, weather, construction, organized events, bad traffic, etc. For example, no software can predict when a vehicle in gridlock is going to start moving again. Sure, the vehicle may only be half a block from its next stop, but it may not move for an extended period of time.
Agencies looking for ‘next stop’ arrival time prediction functionality need to recognize that this information is a prediction—not the absolute truth. This holds true regardless of the software provider chosen.
Friday, August 21st, 2009
There’s more to a Transit ITS implementation than just installing the technology. What should you expect during this critical stage? The better prepared you are, the smoother your experience will be. Here is a free white paper that breaks down the implementation process and describes ways you can prepare for ITS technology changes.
http://www.mentoreng.com/whitepaper/implementation.html
Monday, August 17th, 2009
There is a need to constantly improve efficiency and quality of service in the paratransit and fixed-route transit industries. One of the best ways to revolutionize your agency is by choosing an ITS solution. The proof is in the ROI. Take a look:
The Denver, Colorado Regional Transportation District (RTD) implemented its AVL system to improve bus service, and succeeded in decreasing passenger late arrivals by 21%. Weatherford, et al. Assessment of the Denver Regional Transportation District Automatic Vehicle Location System.
- Prepared for the USDOT (DOT-VNTSC=FTA=00=04), August 2000.
Transit agencies have reported reductions in fleet requirements ranging from 2% to 5% as a result of efficiencies in fleet utilization.
- http://itsweb.mitretek.org/aptsmatrix
Text messages reduce congested voice radio by up to 70%
- http://itsweb.mitretek.org/aptsmatrix
In San Jose, California, a paratransit program equipped with CAD/AVL and an automated scheduling and routing system, realized increased ridership, better on-time performance, and a $500,000 reduction in annual operating costs.
- http://www.itsbenefits.its.dot.gov/its/benecost.nsf/SingleTax?OpenForm&Query=Transit+Management
Scheduling software enabled St. Johns County in northeast Florida to reduce office staff from 9 to 4.5 full-time equivalents, while doubling the number of daily paratransit trips, saving $58,000 per year.
- http://www.itsbenefits.its.dot.gov/its/benecost.nsf/SingleTax?OpenForm&Query=Transit+Management
The Kansas City Area Transportation Authority (KCATA) reduced scheduled travel times by 10% based on data collected from its AVL system.
- http://www.itsbenefits.its.dot.gov/its/benecost.nsf/SingleTax?OpenForm&Query=Transit+Management
In Chattanooga, Tennessee, fixed-route scheduling software improved operations by saving approximately 60 hours per week in operator labor, resulting in a savings of approximately $62,000 per year.
- http://www.itsbenefits.its.dot.gov/its/benecost.nsf/SingleTax?OpenForm&Query=Transit+Management
Friday, August 14th, 2009
It’s true that AVL/GPS systems now come with more capabilities than ever before, like the ability to collect telemetry and other data from the vehicle, and to support richer applications. As this article points out, they also deliver route optimization and planning, and when connected to navigation, allow fleet operators to realize efficiency improvements of 15 to 20%.
Read about these and other AVL/GPS trends, as well as vendor selection tips.
Wednesday, July 29th, 2009
Isolation is a major safety challenge facing mobile workers. During an emergency, a driver may be alone in the vehicle, incapacitated, and unable to communicate with dispatch through voice or text messages. Installing an emergency switch in your vehicles enables the driver to simply hit a button to alert dispatchers or the police to an issue. GPS/AVL can be used to instantly locate the vehicle in trouble and send help.
Friday, July 24th, 2009
When 40% of workplace fatalities result from fleet safety issues, ensuring that effective safety measures are in place is essential. Here is a six-part series outlining ways in which technology can contribute to a safer work environment.
Technology #1: Automatic Vehicle Location (AVL)
Using Automatic Vehicle Location (AVL) technology, dispatchers and managers can see the precise location of their vehicles, and access real-time location information for every vehicle under their care. Combined with GPS integrated with in-vehicle devices, location information is sent back to the office where dispatchers can track vehicle movement on electronic maps, and multi-level grouping and filtering capabilities allow them to focus only on the vehicles relevant to the current situation. AVL benefits both customers and workers. Call times are reduced, the closest available workers will be dispatched immediately, and 911 responders can be sent to the precise location in case of an emergency.
