If you can’t go around it and you can’t go over it, there’s only one thing left to do: tunnel under it.

At least that’s the way some regional planners in Southern California see it. Planners are scheduled to make a decision later this month whether to approve the construction of a tunnel that would run between 10 and 15 miles from Riverside County to Orange County, according to The Associated Press.

The AP reported that the current proposal shows the tunnel taking up two-thirds of a 15-mile corridor connecting Interstate 15 with two toll roads in Orange County.

It sounds like a great plan. Except for two things: First, the tunnel would have to pass beneath the Santa Ana Mountains, a logistical challenge in its own right. Second, the tunnel would be less than a mile from a fault that produced a 6.0-magnitude earthquake about 100 years ago.

Yes, an earthquake fault line.

What’s more, this isn’t the first such tunnel proposed in the area. Earlier this year, planners proposed a tunnel that would connect the Foothill Freeway in Pasadena with the Long Beach Freeway in Alhambra. That plan is still under consideration.

The new tunnel proposal would be a joint effort from the Riverside County Transportation Commission, the Orange County Transportation Authority and the Transportation Corridor Agencies.