Week 2: High Injury Network, Designs, and Roundabouts

This week I decided to look at the high injury network in Fremont and create some designs that promote pedestrian safety.

On Fremont’s Vision Zero Report we get to see the High Injury Network (HIN), which is basically a map that shows where fatal and severe injuries occur. Ever since Fremont adopted Vision Zero back in 2015, it has seen a remarkable reduction in pedestrian collisions.

From this I saw there are many hotspots, especially on arterial roads and intersections which tracks with what I said in the last blog. It is surprising that there are not many collisions on the interchanges for the two interstates (I-880 and I-680) that wrap around Fremont. There are injuries on intersections right next to the highways where cars are entering and exiting at extremely high speeds. The main link in almost all the crashes were high speeds that resulted in drivers reacting slower to their situation.

So what happened between 2018-2022, after Vision Zero was adopted?

Both severe and fatal crashes were almost halved! There are some of the same intersections that have collisions but instead of them being fatal they are severe. It can also be seen that there are still collisions on intersections near the two highways. A new hotspot emerged on Mission Blvd (state highway 262), where it turns from 4 lane road to an 8 lane behemoth that serves both 680 and 880, and even more traffic flowed through as the exit and entrance ramps were expanded.

After understanding the new hotspot, I created some designs for the Warm Springs Blvd & Mission Blvd that looked towards increasing transit reliability and aimed at slowing down cars at the intersection that are coming from I-880. This blueprint can also be emulated at other intersections beside highways.

Of course these are major intersections but there are still accidents at minor intersections and roads, what can be done there? The answer: Roundabouts! They have consistently shown reductions in accidents, greater traffic flows, and fewer polluting emissions. So why not put them on major intersections? Pedestrian safety does not notably increase when there are more lanes on a roundabout, these large roundabouts are more focused on letting cars through, exacerbating the issue of car dependency as it would induce car travel. On top of this, state DOT’s will have a lot of trouble building roundabouts, as they need to completely redesign the intersection or at least purchasing the right-of-ways as roundabouts do take up a lot of space. Which means money and time, these are worsened with larger and busier intersections.

Roundabouts create constant traffic flow, which has a cascading effect on arterial intersections. As traffic will start to build up on the major intersections. This can be beneficial as a few intersections deal with more cars, it lets investment on signaling and design improvements that have already gone into them and future investment have greater yield. So it would be worth it to add, say, a bus priority signal and better pedestrian or bike signaling as many modes converge on these major intersections.

Next week I will look into signaling, so this would mean understanding topics such as traffic signal optimization and finding emerging new technologies that are used abroad and in the US.

This is what I learned this week, hope you learned something new!