We examined 18 round-trip freeway commutes in L.A.
In 14 cases, the evening rush hour was slower than the morning.
Only four commutes had faster speeds in the morning.
The biggest difference:
The 5 freeway, between the 10 and the 605 segment.
The evening rush hour (4-7 pm) traffic heading south moves at just 20.4 mph.
In the morning (7-9 am) the same route heading north travels at 32.9 mph,
61% faster and 11 minutes shorter.
Where does the freeway traffic slow to a crawl in the evening?
Here’s our Top 5 List:
Heading south on the 5 (between 10 and 605)
38.1% slower than the morning commute.
Heading north on the 405 (between 10 and 118)
37.80% slower than the morning commute.
Heading east on the 10 (between Santa Monica and 5)
36.30% slower than the morning commute.
Heading north on the 110 (between 105 and 101)
32.99% slower than the morning commute.
Heading northwest on the 101 (between 5 and 27)
28.85% slower than the morning commute.
Overall, evening freeway commutes are 13.6% slower than morning commutes.
We asked some traffic experts at LA Metro and CalTrans. Their explanation:
There may be many reasons, but the biggest one is that in the morning, people usually have a single destination in mind: getting to school or work. In the evening, people leave work at different times, and often run errands, go to dinner, shop, etc., driving more total miles.
How we did it:
We divided the Los Angeles freeway system into nine different segments. For example, we looked at the 5 freeway from the 10 near downtown till it intersects with the 605 freeway. We also looked at another segment of the 5 between the 10, heading north till it stretches to the edge of Santa Clarita. We did this for seven other freeway segments.
Then, we divided each section into two directions (e.g., east and west on the 10, or north and south on the 5). With the TRANSDEC database, we were able to calculate the average speed in each directions for every hour for 12 months.
Then, we narrowed that down to just the average morning and evening rush hour speeds on each section and compared their speeds in each direction. Morning rush hour is 7-9 am; evening rush hour is 4-7 pm. We compared the morning rush hour speed on a section of the 5 freeway heading south against the evening rush hour speed heading north on the same route. We looked at 18 round-trip freeway commutes in total.
In order to validate the results, we checked our conclusions with LA Metro and CalTrans.