A commute that takes 45 minutes one day, might only last a half-hour the next. Whether it’s because of a traffic incident, weather, project construction or just a more-than-average number of cars on the road, travel times are rarely consistent…

So, wouldn’t it be convenient to know what to expect, before you’re stuck in traffic and it’s too late to take an alternate route?

Of course it would, which is why ADOT displays commute times on many of its freeway message boards in the Phoenix and Tucson areas.

If you’re a fan of those commute times, we’ve got some good news: the number of electronic message boards displaying commute times is due to increase to 76 by late this year (12 of those 76 will display the travel times during both the morning and afternoon rush hours).

Since the expansion of the travel-times program began in September, ADOT has added commute times to 34 freeway message boards, bringing the total to 65 signs that currently display the information for morning or afternoon freeway commuters.

The electronic signs give drivers an estimate of how long it will take to travel to locations, including major cross streets and well-known points along the freeways, such as the I-10 Deck Park Tunnel near downtown Phoenix.

More about the signs

ADOT operates a total of 193 overhead message boards along Arizona highways, including 108 in the Phoenix area and 15 in the Tucson area (five of those in the Tucson area display rush-hour commute times along I-10). Besides commute times, the boards display information on weather-related hazards, crashes, road closures and restrictions, and alerts from law enforcement (AMBER alerts, along with the new Blue and Silver alerts).

Many of you might be wondering how the signs know the amount of time it’s going to take you to get from point A to point B. Well, the times are not the result of just an educated guess; they’re actually continually being calculated by an automated system that uses traffic data and an algorithm – get a more in-depth look at how the times are calculated in this 2013 blog post.

You’ll also find more information about the Traffic Operations Center, freeway cameras and sign installation in our blog archives and over on our YouTube channel.

When issued by law enforcement, Blue and Silver Alerts will be displayed on overhead message boards like this one. When it comes to delivering important safety and travel info to motorists on the road, ADOT’s growing system of overhead message boards (193 of them statewide) helps get the job done. Now, those boards have a new task…

In addition to commute times, travel alerts and various safety messages, the digital signs will also inform drivers of Blue and Silver Alerts.

Don’t feel out of the loop if you don’t know what Blue and Silver Alerts are – they’re very new to Arizona and the laws outlining the alert notification system just went into effect.

Similar to AMBER Alerts, Blue and Silver Alerts are issued by law enforcement officials to notify and seek help from the public.

Silver Alerts will be issued following the report of a missing person who is 65 or older (there are several other conditions that must be met before a silver alert is issued – get all the details by reading the law’s entire text on the state legislature’s site).

Blue Alerts will be issued following an attack on a law enforcement officer if the suspect has fled the scene of the offense (again, there are several conditions that must be met – details can be found within the law’s text).

What to look for on the ADOT message signs

For a Silver Alert, the message will read “Silver Alert - Dial 511 For More Info.” If available, vehicle information also will be displayed.

Personnel in ADOT’s Traffic Operations Center will record a message for 511 with information provided by law enforcement. The messages on the overhead boards will be displayed until the person is found or a time limit of three hours has been reached.

For a Blue Alert, the overhead sign message will read “Blue Alert/License Plate #/Vehicle Description” followed by a second rotating message “Dial 511 For More Info.”

As with a Silver Alert, personnel in ADOT’s Traffic Operations Center will record a message for 511 with information provided by law enforcement. The messages on the overhead boards will be displayed until the suspect is apprehended or a four-hour time limit is reached.

For both Silver and Blue alerts, message boards will be used regionally (not statewide) depending on the area where a search is taking place.

You can learn more about how ADOT uses its overhead message boards by checking out our previous blog posts.

Nobody enjoys being stuck in traffic, but depending on the time and location of your daily commute, backups are sometimes tough to avoid.

Just knowing what to expect on the road ahead often eases some of the frustration. That knowledge also allows drivers to make informed decisions concerning their route, which is why ADOT provides freeway travel times…

What are Freeway Travel Times?
If you travel in or around the Valley, you’ve likely seen freeway travel times listed on one of several dynamic message signs – they tell you how long it’s going to take for you to drive from one point to another (15 minutes to I-10, 34 minutes to Warner Road, etc.). You can also find the travel times on az511.gov.

These times aren’t just the result of an educated guess; they’re actually continually being calculated by an automated system that uses traffic data and an algorithm.

James Minton, a shift supervisor at ADOT’s Traffic Operations Center, explains that the system updates frequently as new data comes in from the road.

Embedded detector loops and passive acoustic devices pick up information and send it back to the TOC’s system. Integrated GPS data also is factored into the equation.

From that data, the system computes an average of all travel lanes, which is then automatically displayed on the dynamic message signs.

Interesting fact: The times are very accurate as of the moment you see them on the dynamic message sign. Of course, if a crash or some other type of traffic slowdown happens, there will be an impact on a motorist’s drive time – consequently, the travel time displayed on the dynamic message signs changes based on the impact of the incident.

More Travel Times
ADOT started displaying freeway travel times on several dynamic message signs in the Valley back in 2008 as part of a pilot program.

Since that time, response from the public has been positive. In fact, the travel time displays have been so well received that drivers are now seeing more of them.

Until just recently, there were travel times displayed on 11 dynamic message signs (6 inbound to downtown Phoenix and 5 outbound).

But, within the past few months, more signs have been added. There are now 32 signs total (15 inbound and 17 outbound) giving drivers information on 60 different destinations and about 400 directional miles.

“A lot of people appreciate the system,” said Minton, adding that more expansion is planned for the future as new projects get built. “People have really responded well.”

Human factor
While an automated system does the calculating, ADOT employees are the ones who watch the roads (there are 180 cameras in the metro-Phoenix area alone) and display messages on traffic and road conditions, along with potential alternate routes and other important messages.

Minton and his team also record the travel times each day to spot trends and make sure the system is working the way it is supposed to be.

Active Traffic Management
Assistant State Engineer Reza Karimvand says that being able to display travel time information and messages to drivers is a valuable tool when it comes to managing traffic.

With 106 dynamic message signs in the Valley, there’s big opportunity to share important traffic-related messages with drivers. Not only does the information assist drivers on the road, but the details can actually work to improve traffic.

“If we can divert cars from the scene of an accident, it helps the traffic flow,” he said.

We’ve got a blog post coming up real soon that’s going to focus on Dynamic Message Signs (Don’t know what those are? Keep reading!).

That blog post isn’t ready quite yet, so in the meantime we wanted to at least get started by defining a couple of terms for you …

First up, Dynamic Message Signs: These are the large signs over/near roadways used to display messages to the public. You’ll often see travel times posted on these signs during rush hours or safety messages and other travel information.

The larger DMS have three rows of 18 characters. Each of those characters measures 18 inches tall.

Now that you know what DMS is, take a look at a Node Building. These “buildings” are about the size of a typical storage shed and are located near the roadway. There are several node buildings in the Phoenix-metro area.

Node Building

These nodes are filled with equipment capable of collecting regional information (e.g., from various controller cabinets) and sending it to the TOC. Node buildings are equipped with fault tolerant air conditioning systems to maintain moderate summer temperatures.

OK … now you’ll have to stay tuned for a more in-depth blog post on Dynamic Message Signs.

Transportation Defined is a series of explanatory blog posts designed to define the things you see on your everyday commute. Let us know if there's something you'd like to see explained ... leave a comment here on the blog or over on our Facebook page!