Corona 91 Carmageddon Weekend Traffic Patterns

Graphic: RCTC

by: Nicholas Ventrone, Community Engagement Director

As of 12pm - Source: Caltrans
Here's an ongoing traffic report from Caltrans regarding the Carmageddon Weekend in Corona.

12 Noon Friday (9 hours until closure)

As of 12 noon Friday, traffic was flowing smoothly through the 91 Carmageddon zone on both the freeway and surface streets.

Hit-and-run collision on northbound SR-57 has traffic backed up through Brea Canyon. Some reduced speeds on the eastbound I-10, and the I-15 in between the SR-60 and the I-10.

Traffic was much lighter than I predicted this time of the day which normally begins to back up on Friday afternoons at noon.

1PM Friday (8 hours until closure)

As of 1pm - Source: Caltrans
As of 1PM, a reported hazard in Corona at Lincoln has eastbound traffic backed up to the 71. Corona surface street traffic is still flowing well.

Hit-and-run collision on northbound SR-57 cleared and traffic is beginning to thin out. Eastbound 10 and 60 beginning to show signs of slowing through West Covina in between I-605 and SR-57.

Inland Empire traffic still flowing well for both the 10 and 60 in Ontario with some reduced speeds on the I-10 just east of Ontario Airport. I-210 still a good drive in between SR-57 and San Bernardino. Traffic appears lighter than normal this time on a Friday afternoon.

2PM Friday (7 hours until closure)

As of 2pm - Source Caltrans
As of 2PM, the reported hazard in Corona at Lincoln has cleared but eastbound traffic is now starting to show its typical peak hour slowing to Coal Canyon Rd. Corona surface streets are starting to get heavy but the speeds are still good.

Another collision on northbound SR-57 occurred on the 60 in Diamond Bar involving a big rig which is seriously affecting the recommended detour route in the peak direction. The 57 north is backed up through Brea Canyon to Imperial Highway. Once past the incident the 60 is a good drive all the way to the I-15.

I-10 east is beginning to slow through Claremont from Garey until Mills. I-210 has some reduced speeds from the I-605 to just west of Towne. I-15 is slow between the 60 and I-10 with some segments of slowing to/from the 91.

3PM Friday (6 hours until closure)

As of 3pm - Source Caltrans
The freeway system is beginning to look like your normal Friday afternoon commute.

The collision on the northbound SR-57 at the 60 has made a mess of the RCTC-recommended detour route. The 57 north is backed up through Brea Canyon into Placentia. The eastbound 60 is backed up from Downtown LA. The 10, 210 and the 60 are now showing signs of reduced speeds between the 57 and I-15.

The Corona Crawl is officially underway in Corona. The 91 is heavy from Weir Canyon to Main Street in Corona.

As of 3pm - Source Caltrans
But what I'm finding very interesting that the press has yet to cover is the 91 Express Lanes traffic choking up at the toll antenna area. I notice that this is becoming routine during super-peak afternoon rush hours.

I've passed through this area going toward Orange County in December during the evening rush hour a number of times and sometimes saw the eastbound HOT lanes congested; I've always thought it was due to an incident blocking the lanes since the news media has been relatively silent on this issue.

Now, I suspect the back up's which sometimes go all the way to the 55 are now due to 3-person carpools having to weave to the single 3+ carpool lane at the toll collection point. I believe more FasTrak-registered 3+ carpools are using the single 3+ lane than it can handle.

As a result, the Express Lanes were backed up to Imperial Highway at the time of this update with a posted non-HOV toll of $10.15. Those back-up's should not be happening in the express lanes, period.

Concept: Digital signs should designate the 91 Express Lanes as a 3-person carpool lane whenever it approaches full capacity or speeds drop below 45-50 mph.
Note: Concept only. Not endorsed by OCTA, Caltrans or any other entity.

Here's what state and local officials should employ, immediately. First, if the 91 Express Lanes shows any kind of peak-hour slowing or approaches full capacity, it should become a dedicated FasTrak-registered 3-person carpool lane. That means, toll-paying, non-HOV traffic may not enter until the congestion clears. Only FasTrak-registered 3+ carpools may enter during these times. The toll lanes are sold out! Once lane capacity opens up, the signs would revert the lanes back to high occupancy toll.

Second, officials should phase out the separated 3+ lane and utilize the switchable transponder so that 3+ carpools can self-declare their vehicle occupancy without having to weave to a separate single carpool lane. The overhead antennas would record the toll transaction as a 3+ carpool and display a different color beacon light to law enforcement for transponders switched to HOV 3+.

Switchable FasTrak's are already available for accountholders because the LA Metro ExpressLanes uses this method; it needs to be made the norm. That will eliminate the need to maintain the separate 3-person carpool lane. Further down the road, once the toll bond debt is paid off, officials should eliminate the FasTrak transponder requirement for 3-person carpools all together and maintain the toll option for non-HOV's whenever space is available at the market rate. A stronger CHP presence would enforce all carpool and toll payment violations with heavy fines and points for deliberate violations and cheating.

4PM Friday (5 hours until closure)

Typical Friday afternoon at 4pm, although the 91 is not as chaotic as I thought it would be, at least for now. The northbound 57 is still recovering from the big rig collision at the 60 earlier in the afternoon. The I-15 is also very tough with its typical slowing up the hill toward Dos Lagos. Traffic on Corona's surface streets are surprisingly lighter than normal but still high in volume. Same with the 71 between Chino and the 91. The eastbound 91 Express Lanes is heavy at the toll collection point to the 55. The regular lanes are jammed stop-and-go from the truck scales to the 241 then slow-and-go to Serfas Club.

As of 4pm - Source Caltrans

5PM Friday (4 hours until closure)

Traffic on the 91 begins to thin out but remains very heavy. SR-57 north remains very congested through Brea Canyon. Another traffic collision is reported in Diamond Bar. This one was along the southbound 57/60 merge at Grand Avenue.

As of 5pm - Source Caltrans

6PM Friday (3 hours until closure)

7PM Friday (2 hours until closure)

Traffic on the 91 opens up much earlier than usual during the Friday rush hour. 

8PM Friday (1 hour until closure)

I originally predicted that traffic would be chaotic on the 91 during this hour. The wide open freeway suggests otherwise. The actual chaos during this rush hour occurred in Diamond Bar where yet another traffic incident was reported that backed up northbound SR-57 through Brea Canyon.

 9PM Friday

At the time of the shutdown, there was a minor backup on the eastbound 91 from the 71 to Coal Canyon for about an hour. But by 10:30pm, it had completely cleared for the night. Traffic on Corona surface streets was clear.


History repeats itself as traffic in Corona was much lighter than expected. The eastbound 91 backup stretches from the 71 to just east of the 241 Toll Road at Coal Canyon Road. However, the traffic collision chain at the SR-57/60 merge in Diamond Bar continued and backed up traffic along the primary detour route for most of the day.


Traffic in Diamond Bar this day was not nearly as bad as Saturday with fewer traffic collisions in this area. Circle City's surface streets through crowded and busy remained gridlock free and were moving along.