A Better Way to Collect Travel Time
Accurate travel time measurement and analysis
The Problem Traffic Engineers Face
Roadway performance degrades over time.
Traffic engineers have to monitor and measure travel performance metrics in order to manage roadway performance. Motorists, freight operators and public transit agencies all depend on accurate travel-time data to set their schedules. Accordingly, the Federal Highway Administration (FHWA) has asked agencies to improve the quality of travel-time measurement through the use of reliable, real-time data.
Most federal grants require that travel performance metrics are constantly monitored and reported.
And estimating travel time is not an easy task.
Historically, travel time was estimated using the floating car methodology. People would actually drive the traffic corridor with a stopwatch and estimate actual travel time. This method is not sustainable. Also, this method only estimated travel time data for a snapshot in time.
Next came the age of the inductive loop and radar. Engineers tracked mid-block vehicle speed using inductive loops or radar. This speed was used to extrapolate travel time between two points. However, due to vehicle congestion that could occur at various points of the roadway, this method has been found to be less than desirable.
When cell phones became prevalent, Bluetooth sniffers were used to calculate travel time between two points. Studies indicated that Bluetooth-based sensors have very low sampling rates (between 3-12%) and short range.
A Better Way to Collect Travel Time
Accurate travel time measurement and analysis
Rhythm Engineering introduces In|Time – a tool for accurate travel-time measurement and analysis.
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In|Time delivers precise data at a very low investment.
In|Time Travel-Time Measurement Solution measures real-time travel time data along a corridor or arterial by capturing MAC addresses of WiFi devices in vehicles as they pass.
“Travel time data will help me prove that we’ve been good stewards of the city funds, that we’ve spent the money wisely. If travel time is down, that’s a BIG thing.”
Jim Dickinson, P.E.
Principal Traffic Engineer
West Des Moines, IA
“When you don’t measure travel time, you are guessing. Nobody likes to guess. You want to have accurate data that will give you a solid foundation to make decisions.”
Larry Haas, P.E.
Traffic Operations Engineer (fmr)
CDOT | Greely, CO
How Does It Work?
A MAC (Media Access Control) address is a unique hardware identifier assigned to any Ethernet or WiFi device. All cell phones and most newer cars have a unique MAC address associated with them.
In|Time sniffs for MAC addresses around it. Each MAC address is captured, hashed (anonymized), given a unique ID and time-stamped at Point A and Point B.
The difference between the timestamps yields the actual point-to-point travel-time. Any anomalies beyond a certain tolerance are rejected by In|Time’s data-acceptance model. Therefore, any travel-time captured and reported is very accurate.
In|Time passes the unique ID on to the In|Time Data Controller. This unique ID or “fingerprint” is then tracked throughout the travel route. Then it uses complex and extensive statistical modelling to compute precise travel time.
The actual MAC addresses are never stored, which safeguards the integrity and anonymity of the motorists.