Ralston & El Camino lane reassignment proposal John Boykin , The Belmont traffic safety commission considered a proposal to reassign lanes on eastbound Ralston at El Camino, to create a dedicated right turn lane. The commission was reluctant to do so, citing one main concern. This presentation is to address that concern. This presentation must be viewed in Slideshow mode.

The Problem Eastbound Ralston has no dedicated right turn lane onto southbound El Camino. Yet it has 2 (underutilized) left turn lanes. So drivers wanting to go toward San Carlos must share a lane with through traffic. This creates a bottleneck, backing up cars and impeding the smooth flow of traffic at Belmont’s most important intersection.

The solution: Reassign lanes Status quoProposal

Concern: Lanes offset (jog) The commission’s main concern was that, if we shifted the two through lanes to the left, they would no longer line up with the lanes on the opposite side of El Camino. Cars would have to jog to the right as they crossed the intersection.

True. The question is, How would this offset compare with existing nearby offsets that we take for granted?

Widening road mouth downstream The offset could be reduced with a modest modification to the east side of Ralston (downstream). Let’s zoom in on the area inside the circle.

Status quoModify from this… Widening road mouth downstream Island is 9’ wide—about the width of 1 lane of traffic Road mouth now wider, angling toward incoming cars & lessening offset All remaining pictures will show this modification …to this

So here is the offset we would have (dotted yellow line). We’ll come back to this. But first, let’s look at a few nearby precedents for comparison.

Precedent 1: 180 ft. upstream

The first precedent is right here —180 ft. upstream. Let’s zoom in on it.

…and straighten out again here. Lanes go straight here… …start jogging here to the right …

How much is this existing upstream offset that we take for granted? Let’s trace it to find out. First, let’s imagine what we would have if the lanes continued going straight.

Now, let’s imagine extending the downstream lane divider just to see where that would lead.

It now becomes apparent that traffic is currently jogging over about one lane’s worth. Here’s another view of that

The blue line here traces the offset.

Now, let’s see how that same offset would look if we were to pick it up and superimpose it over the intersection. Blue line = existing upstream offset

Here is the existing offset superimposed over the proposed lane configuration. Let’s compare this with the proposed offset.

So the proposed lane configuration would give us an offset nearly identical to the one we already have 180 feet upstream. Blue line is existing upstream offset. Yellow dashed line is proposed offset. Now let’s zoom back out to see the whole picture.

… to here. The proposal basically just relocates the existing jog from here…

So instead of jogging before the intersection…

…traffic would go straight and then do the jog through the intersection. Northbound and southbound cars would peel off to the left and right.

That’s just the closest precedent. Let’s look briefly at 2 more.

Precedent 2: El Camino at Holly

Holly Northbound El Camino at Holly in San Carlos Green line traces the offset

Holly Now let’s transpose this offset onto the proposed intersection Green line = existing offset at El Camino & Holly

Holly The proposal nearly matches the offset we take for granted at Holly. Yellow dashed line is the proposed offset. Green solid line is the El Camino- Holly offset.

Precedent 3: Woodside Rd. & Veterans (southbound 101 offramp onto Woodside Rd.)

Woodside Rd. Offramp from southbound 101 onto westbound Woodside Rd. in Redwood City. Red line traces the offset.

Woodside Rd. Woodside Rd. offsets to the left. Ralston would offset to the right. So, to superimpose Woodside Rd.’s offset onto Ralston’s, we first need to make a mirror image of it… Red line = existing offset at Woodside Rd.

Woodside Rd. …like this. Then we’ll need to pivot it a little clockwise to match Ralston’s orientation… Mirror image

Woodside Rd. …to this. Pivot point …from this…

Comparison The proposed offset is much less than the offset we take for granted at Woodside Rd. Red solid line is Woodside Rd. offset. Yellow dashed line is proposed offset.

Let’s review how the 3 nearby precedents compare with the proposal

PROPOSAL …and much less than Woodside Road’s … and to Holly’s… Here’s the offset resulting from the proposed lane reconfiguration… …very comparable to the one 180 feet upstream on Ralston…

In short, we need not be concerned about the offset resulting from the proposed lane reconfiguration, because the new offset would be very comparable to existing offsets: 180 feet upstream on the very same road northbound El Camino at Holly …and much less than the existing offset at Woodside Rd. The biggest problem at both Woodside Rd. and Holly is poor guidance through the intersection to the correct lane on the opposite side. We must put guidance buttons in the Ralston-El Camino intersection.

Summary The traffic commission should reconsider the proposal to create a dedicated right-turn lane from eastbound Ralston onto southbound El Camino. The commission's key concern can be put aside because the offset that would be created through the intersection is comparable to other nearby offsets that we have no problem with now. Status quoProposed

We would only need to make 3 modest modifications. 1. Taper the island on the east side of the street and re-angle the left-turn lane with it Status quoIsland tapered

2. Paint new lane stripes and direction arrows Status quo: Jog before intersection Proposed: Jog through intersection

3. Add guidance buttons through intersection Like Holly does well here (Not like Holly does poorly here)

Conclusion: Fix the bottleneck Creating a dedicated right-turn lane from eastbound Ralston onto southbound El Camino will alleviate the bottleneck at Belmont’s most important intersection will create an offset comparable to other acceptable offsets nearby can be done with only modest modifications Status quoProposed