FAIRFIELD — How does a pedestrian cross the road? It all depends on the intersection.

Some intersections in town, like one on the Post Road near Grasmere Avenue, have the latest pedestrian lights, with audio and visual cues, including a countdown to how much time is left before the traffic gets the green light.

At others, there may just be the painted white lines of the crosswalk, along with bright yellow road signs to alert motorists to the existence of that crosswalk. Downtown, you might find a button to push, but while that will stop traffic on the Post Road, vehicles coming out of side streets still have a green light. Still other downtown crosswalks have a dedicated pedestrian phase light, which displays a hand when it is not safe to cross.

On Fairfield Beach Road at the entrance to Penfield Beach, and on the Old Post Road in front of St. Paul’s, there are signs in the middle of the crosswalks to remind motorists of state law that requires them to yield to pedestrians.

Why aren’t all intersections treated the same? While it may seem haphazard to some, Lt. Robert Kalamaras said one of the main determining factors is simply pedestrian count: how many people cross the street at that particular intersection on an average day.

Whether a street is a local road or a state road is also a factor, with the state Department of Transportation having the final say on its roads. And cost comes into play when intersections and crossings are given upgraded dedicated pedestrian signals, such as the one on the Post Road near Grasmere and Riverside.

That pedestrian signal complies with the Americans with Disabilities Act, which means that the sidewalks themselves need to be brought up to current ADA standards, with curb cuts and landing pads. The cost can end up being $200,000 or more, according to town officials. The signal itself actually tells pedestrians to wait when they first push the button. When they have the signal to cross the street, there is an audible tone and the light also shows a count down for the time left to safely cross.

“There are engineering protocols that are used, along with the Manual on Uniform Traffic Control Devices, which gives us certain guidelines that we adhere to,” Kalamaras said.

Some of the MUTCD guidelines for crosswalks include:

Crosswalks should be marked at all intersections where there is substantial conflict between vehicular and pedestrian movements.

Marked crosswalks also should be provided at other appropriate points of pedestrian concentration, such as at loading islands, mid-block pedestrian crossings, or where pedestrians could not otherwise recognize the proper place to cross.

Crosswalk lines should not be used indiscriminately. An engineering study should be performed before they are installed at locations away from highway traffic signals or stop signs.

Because non-intersection pedestrian crossings are generally unexpected by the road user, warning signs should be installed and adequate visibility should be provided by parking prohibitions.

The Police Commission recently received two separate requests regarding crosswalks. One asked for one of the moveable signs to be put in the crosswalk at Stratfield Road and Bond Street. There is no traffic light or stop sign at the intersection and it is a state road. The commission will ask for the state DOT’s recommendation. There are yellow signs on either side of the crosswalk to alert motorists.

Kalamaras said, while the Police Commission has approved the moveable signs for other crosswalks, it is often only done if there is someone — like the crossing guard at St. Paul’s — to put the sign out and bring it back inside.

The other request is to install a crosswalk across Black Rock Turnpike from Tahmore Drive to Old Black Rock Turnpike. The commission postponed that decision and William Hurley, the town engineer, explained that the town would be required to make the ADA upgrades to the sidewalk. The Police Department will conduct counts to help determine if the crosswalk is warranted.

Even with the crosswalks, people often ignore them, as evidenced in a recent fatal accident on Black Rock Turnpike. An 86-year-old woman died after being hit by a car while crossing in the middle of the block, not using the signalized crosswalk at the corner.

“Given the recent events on Black Rock Turnpike, we always encourage pedestrians to look for the nearest crosswalk,” Kalarmaras said. If a crosswalk is not available, he said, pedestrians should cross at street corners and intersections.

Motorists should also be aware, he said, that Connecticut is a “yield” state, where motorists are required to yield the right of way to pedestrians in crosswalks.

greilly@ctpost.com; @GreillyPost