King County Metro Spot Improvements

Thought it'd be fun to look at some spot improvements King County Metro has done. The 2024 report was just published this month. Below will detail a handful of spot improvements alongside previous ones from the 2022 report and 2023 report.

OverviewElliott Ave W and 15th Ave NW

edit: the spelling of Elliott Ave W has been corrected where possible.

Cars from W Mercer Pl were refusing to yield to buses traveling northbound on Elliott Ave W. Shark tooth yield lines were added as well an additional yield sign. These improvements saved northbound buses around 7 seconds on average.

The Elliott Ave W BAT lane hours were extended to operate in both directions rather than only southbound in the AM peak and only northbound in the PM peak, saving buses around 5~12 seconds per trip during peak time.

At 15th Ave NW and NW Market Street, SDOT added a queue jump in the southbound direction saving 15 seconds per trip.

Rainier Ave S

For the southbound Rainier Avenue S, there were too many cars trying to turn right onto S Alaska St. The signal was modified to add in an additional right turn arrow phase during left turns from S Alaska St saving around 5~11 seconds per trip.

A new traffic signal for left turning cars and concrete median for pedestrians was added to the S King Street & Rainier Ave intersection. Unfortunately the new median also blocks buses trying to enter the left turn lane onto S Jackson Street. SDOT modified the left turns to occur at the end of the northbound green phase rather than the beginning. This improvement allows buses to enter the left turn pocket, saving around 17 seconds per trip.

(For a bit more context, both S Jackson St and S King Street can cross under I-5. Other nearby east-west streets such as S Weller St and S Lane St are blocked by I-5.)

Redmond Technology Station

The protected left turn into Redmond Technology Station was too short delaying buses. Metro extended the northbound left turn phase, saving the buses around 17 seconds per trip.

Renton

The northbound left turn from Logan Ave S to S 2nd St was completely blocked by pedestrians right after the Renton High School dismissal time. The green phase was extended after the pedestrian phase ends, saving 8 seconds from each trip time.

The existing BAT lanes on Rainier Ave S from S 3rd Street to S 4th Place were painted red with BUS only parkings. The southbound BAT lane was also extended one block north to S 2nd Street. The 3 blocks of BAT lanes saved an amazing 71 seconds per transit trip during peak times.

Kent

The westbound, northbound, and southbound buses at SE Kent-Kangley and 132nd Avenue SE were frequently blocked by cars at the intersection waiting in the through lane direction. Fortunately they all had far-side bus stops and also dedicated right turn lanes that had less traffic. This allowed Metro to modify the signage legally allowing the buses to travel straight through to the far-side but stop. The westbound buses saved around 17 seconds per trip.

The eastbound direction has a near-side bus stop because the Safeway shopping center is in the southwest corner. Metro instead plans install a queue jump signal for the eastbound direction.

The previous westbound James Street configuration had one left turn lane, one center through/right lane and one dedicated right turn lane. Due to congestion on Washington Ave N, right-turning cars heading west on W James St would occupy both center and right lanes, blocking westbound buses. The city of Kent modified W James St to instead have one dedicated lane per direction. Now when Washington Ave is congested, right turning traffic from W James St will only block the right lane and leave the center lane free. Westbound buses can choose whether to stay in the right lane or now use the center lane if it's less obstructed. This modification saved around 6 seconds per trip.

Conclusion

Each spot improvement typically shaves off around 15 seconds per average trip, or up to 71 seconds for some of the more complicated improvements. Unsurprisingly, larger improvement such as BAT lanes are much more effective than smaller ones such as traffic light retiming. Even those smaller spot improvements along a route can add up and improve the total trip time by 3~4 minutes for a relatively low cost. Finally, bus speed increases allow King County Metro to provide higher frequency with the same number of buses.