To explain why Palo Alto is about to launch the biggest -- and possibly the most disruptive -- infrastructure project in its history, the city's new consultant on Thursday showed an assembled crowd a video of a SUV speeding toward the railroad tracks and stop just as the gate came down onto its roof.

The vehicle then stopped and, after a few seconds of hesitation, backed up to safety before the train passed.

"Luckily, no one is behind him and he was able to back up before the train," said consultant Etty Mercurio of the firm AECOM, which has been working with numerous Peninsula cities, including Menlo Park, Burlingame and now Palo Alto, to come up with ways to resolve the conflicts between trains and cars.

The video, shot at Burlingame's Broadway crossing, was followed by several other examples of near-misses from the Peninsula. Recently, Mercurio said, she saw cars waiting at the Charleston Road crossing as a Caltrain train passed by. Then, when drivers noticed that another train was set to arrive a minute later, they sped forward to get past the gate before it closes again.

"We want to eliminate that conflict between trains, and vehicles and bicycles and pedestrians," Mercurio said at the meeting. "If we eliminate that conflict, we can eliminate delays, reduce congestion and really improve safety at these at-grade crossings."

The standoffs between cars and trains are expected to become much more common in the coming years, as Caltrain moves ahead with an electrification project that will send more trains up and down the Peninsula. The number of trains on a weekday is set to increase from 92 to 114, Mercurio said. During peak hours, about 20 trains will move through Palo Alto's 4-mile corridor, or roughly one every three minutes.

"We want to eliminate that conflict between trains, and vehicles and bicycles and pedestrians," Mercurio said. "If we eliminate that conflict, we can eliminate delays, reduce congestion and really improve safety at these at-grade crossings."

More than 120 people attended the Thursday community meeting at Mitchell Park Community Center to learn about the city's plan to address this conflict by physically separating the roads from the rail corridor. Palo Alto is now in the midst of winnowing down its options for "grade separation" at Palo Alto Avenue, Churchill Avenue, Charleston Road and Meadow Drive.

While the city has been talking about grade separation since at least 2009, officials are finally making progress in determining what this would look like at each of the crossings. In April, the council approved the city's $1.3-million contract with AECOM to serve as the lead consultant. Earlier this month, a new citizens group was selected to work with staff and consultants on the project.

After spending much of 2017 soliciting ideas, Palo Alto ended up with a master list of 34 ideas by early this year, said Chief Transportation Official Joshuah Mello. In recent months, the City Council and its Rail Committee winnowed down the list to seven options.

Most recently, the council eliminated from consideration the idea of doing grade separation at Churchill Avenue after an analysis indicated that doing could impact dozens of properties. Specifically, the council scrapped the "hybrid" option, which would have lowered Churchill Road and raised the tracks over the road. The option would have impacted about 14 properties, according to the study. The "reverse hybrid" option, which involves a raised road and lowered tracks, would have resulted in up to 42 property seizures. It too was tossed from consideration.

The only option now considered for Churchill is simply closing the street to traffic at the rail crossing and making other improvements to compensate for traffic-circulation deficiencies that may result from the closure, Mello said.

At the same time, the idea of raising or lowering the tracks at the two southernmost crossings -- Charleston and Meadow -- remains very much alive. Last week, the Rail Committee considered a study that showed that the "hybrid" option on Charleston could be achieved without any property impacts. At Meadow, which would potentially share the embankment with Charleston, the project would only impact portions of two driveways.

Other options on the table for Meadow and Charleston are a tunnel, a trench and a viaduct for the train -- alternatives that would leave the roads in their current alignment.

At the northernmost crossing, Palo Alto Avenue, the city is considering closing the road in conjunction with other traffic improvements such as widening University Avenue or building an undercrossing for pedestrians and bicyclists at Everett Avenue. Another alternative is placing the roadway under the railroad, much like Menlo Park is planning to do at Ravenswood Avenue.

The city is also still leaving in the mix the popular idea of digging a citywide deep-bore tunnel, though city officials and most members of the City Council had conceded months ago that such a project would probably be far too expensive to be considered feasible.

During the Thursday meeting, Mercurio went over the various options in greater detail, describing how far the tracks and roads would have to be raised under each alternative and the length of the "shoofly" tracks that would need to be constructed in most designs -- temporary tracks that would likely be built along Alma Street while grade separation is being constructed.

After the presentation, residents were invited to get more details at tables devoted to each crossing (as well as to tunnels and to traffic), where they debated the merits of hybrids versus reverse hybrids and raised concerns relating to privacy impacts, noise and traffic circulation.

Even so, the meeting left many in attendance thirsty for more information. Residents asked about the cost of the various options, a topic that the consultant is still studying (Mercurio said costs will be available at the next meeting, which is scheduled for Nov. 28). One person asked about privacy impacts of trains, which he said should be elevated near Charleston (he was told that soundwalls can be a possible solution).

Another asked about what the project would do to traffic. Mercurio responded that the goal is to maintain the existing traffic patterns through construction phasing.

"Grade separation is very complex and when you go to construction ... the appetite to keep roads open and closed can influence the duration of construction," Mercurio said.

Mello said that once the city narrows down to six ideas, it will be able to devote far more resources to each option, which includes performing traffic studies and creating 3D simulations. After selecting its preferred options, the city plans to move ahead with design work and environmental analysis, which it hopes to complete by 2023. Under this schedule, which Mello described as "ambitious," the project would be complete by 2029.

More information about Palo Alto's grade-separation program is available here.