November 2019


LongCommute

Not how the crow flies to get to work each day

by George Taniwaki

I really don’t like to drive to work. I’ll do almost anything to avoid a long commute. For most of my adult life I have either walked or ridden a bus to get to work. Yes, it’s possible. I always chose an apartment to rent or house to buy based on how close it is to my job. And once I’ve found a place to live, I usually reject a new job unless it’s within walking or riding distance. It helps that I like living in big cities.

But I just started a contract assignment in Mountlake Terrace, a suburb of Seattle about 20 miles from where I live as the crow flies (see image above, or not). This isn’t the longest commute in my life, but the first long one in a few decades. And it’s the first long commute where I’m driving alone rather than in a carpool.

Google Maps, initial attempt

The traffic in Seattle is awful. To reduce my commute time, I’ve decided that starting my drive at 6:30 and working from 7:30 to 4:00 will help. Before my first day to the job site, I pull out Google Maps and plot my route (see Fig 1).

CommuteToWorkI405Label

Figure 1. My first route to the office, average 42 minutes every morning

For the analysis in this blog post, I split my drive into segments based on type of driving. Segment A consists of surface streets from my house to the highway. B is 17 miles at highway speed driving north, away from the city, C is a slow slog where I double-back and join the commuters coming into town, and D is the final, short segment of surface streets to the office.

The table below shows details of my commute. Most of it is tolerable. But notice that segment C (the red zone) constitute less than one-sixth of my commute distance but over one-third of my commute time.

Map Description

Dist.

Speed

Elapsed Time

A Surface streets from home to SR520

3

30

6

B SR520 to I-405 to I-5

17

60

17

C I-5 to Mountlake Terrace

4

15

16

D Surface streets from I-5 to office

1

20

3

TOTAL

26

37

42

Google Maps, redux

After a couple weeks of following this route, I’ve learned which lanes to use on which segments to slice a few minutes off my commute. But I think I can still do better. I check Google Maps for some alternatives. This time it gives me a completely different, and unexpected, route. It tells me to go a few miles out of my way south to I-90 and drive north through the city on I-5 (see Fig 2).

I-5 in downtown Seattle is one of the most congested highways in the U.S. I get queasy every time I drive it worrying about getting stuck. But maybe it’s not so bad at 6:45 AM, which is about what time I will get there. So I trust Google Maps and try it.

CommuteToWorkI5Label

Figure 2. Google Maps’ new suggestion, average time 44 minutes

It works. I try the route on two consecutive days. The table below shows the average results. There is congestion on I-5 between I-90 to Olive Way (Segment C red zone) but it is a shorter segment than my previous commute. However, the route is longer, so it doesn’t save much time. Further, I don’t like this route because it limits my options. If there is an accident or other delay, I will be stuck in traffic with no easy way to avoid it.

Map Description

Dist.

Speed

Elapsed Time

A Surface streets from home to I-90

4

30

8

B I-90 to downtown

8

60

8

C I-5 to Olive Way

2

20

6

D I-5 to Mountlake Terrace

14

60

14

E Surface streets from I-5 to office

1

20

3

TOTAL

29

42

39

Waze to the rescue

Waze is a GPS navigation app originally developed in Israel but quickly went global. It uses traditional digital map data and combines it with real-time location data from users including speed, route, reports of traffic jams, accidents, police speed traps, and gasoline prices at nearby stations. Thus, the more people who use it, the more accurate it becomes.

Waze also shows you the current toll price (Seattle uses variable toll pricing) and lets you avoid tolls, ferries, or highways, if desired, when choosing a route.

Google (now Alphabet) acquired Waze in 2013 but it remains a separate entity from Google Maps. Because Waze collects potentially personally identifiable information (PII), it has a less restrictive user agreement than Google Maps and warns users of that fact. (Though most people never read the agreement and just click “I accept”.)

Generating a route is a highly resource intensive calculation that often involves machine learning. To simplify the work, Google Maps generally limits routes to major arterial streets. Waze combines those calculations with the actual routes users are taking to find the minimum travel time. Thus, Waze often creates routes that run through residential neighborhoods. Of course, the neighbors sometimes complain or even fight back by generating fake route data (Wash Post, Jun 2016).

Figure 3 below shows the route Waze recommends for my commute. It looks just like the original route that Google Maps suggested, except for the last segment. I still take the I-5 cloverleaf, but instead of continuing onto I-5, it has me veer right and use side streets to get to the office.

CommuteToWorkI405LocalLabel

Figure 3. My new favorite route to work

Map Description

Dist.

Speed

Elapsed Time

A Surface streets from home to SR520

3

30

6

B SR520 to I-405

17

60

17

C Surface streets from I-405 to office

6

30

12

TOTAL

26

44

35

The best part is that I can see I-5 from the I-405 off-ramp. When traffic is light (speed is 30 mph or more), I can veer to the left and take I-5 to the office. When I-5 is congested, I can veer to the right and take surface streets. While on the surface streets, I can continue to see I-5 and confirm whether I made the right decision and improve my choice for future days.

Waze leads me astraze

With my success with Waze in the morning, I decide to use it for my evening commute home as well. As I turn onto I-5, Waze tells me there is road kill ahead. I wonder where. Then suddenly I see a raccoon and am jolted by the thump. It saddens me to know that I’ve squashed an innocent animal under my tires, even if it is already dead.

The rest of the commute home is uneventful until Waze tells me to exit I-405 at NE 85th St in Kirkland (Fig 4b), 4 miles before my usual exit at SR520 (Fig 4a). Gee, that seems like a bad idea. Should I ignore Waze and keep going straight? Or should I take the exit? Maybe there is an accident on my regular route. Or maybe the crowd of Waze users knows a sneak route. Well, Waze has been pretty accurate so far, so I take the exit.

Ugh, what a mistake. Driving east on NE 85th St takes me straight into a huge traffic jam on Redmond Way. Also, there is a giant construction project on the Microsoft campus, so West Lake Sammamish Pkwy is overflowing with drivers avoiding lane closures on 156th Av NE. My commute today is more than 35 minutes longer than usual. I won’t do that again.

CommuteToHomeI405Label CommuteToHomeI405LocalLabel

Figures 4a, b. My normal commute home, Waze suggestion for 11/21/2019

Conclusion

Both Waze and Google Maps show you unexpected options and are likely to give better routes than you could find on your own. Overall, my experience with Waze was better than Google Maps, but both could use improvements.

* * * *

All this talk about commute time has me remembering a brain teaser from my childhood. Let’s say I want my average commute speed to be 40 mph. One day, I get stuck in traffic and cover the first half of the distance to work at an average speed of 20 mph. How fast do I have to drive on the second half to meet my goal? Hint: The answer is not 60 mph or even 80 mph.

NorthGateInside SouthGateInside

New gates seen from the backyard: Left-hand outswing gate on north side of house, Narrower right-hand outswing gate on south side of house

by George Taniwaki

There are two gates between the front and back yards of my mother’s house, one on the north side and one on the south side. In my mom’s neighborhood, all fences have six-foot cedar pickets. All the gates are hung so that their hinges are attached to adjacent 4"x4" posts. The gates swing toward the front yard and the gate hinges and latches face the front yard. Views of the new gates from the backyard are shown above.

Both old gates at my mom’s house are probably three decades old. They are weathered and sag so much that they drag on the ground. Neither was particularly well-designed or was hung properly when new, so the problem has been festering for a while. I finally decided to replace them both. Each new gate took about three days to build and install. (Yes, I’m a really slow woodworker and I could never make a living doing this.)

Why gates fail

Before I begin to build the new gates, I think about why the old gates failed. There seems to be two problems. They were not designed to absorb the forces on them and they were not built using good construction practices.

The main force on the gate is gravity. This force is transferred to the hinges. The gravitational force is spread across the entire width of the gate (Fig 1a). But the hinge support is not. This causes torque which also has to be absorbed by the hinge and the gate frame.

This torque causes stress which can cause the gate to fail. The hinge post can rot or get loose or the screws on hinge can come loose (whole gate tips), the gate can split at the joint between the stiles and rails, or the gate can rack (Fig 1b).

GateStaticForces GateFailureModes

Figure 1a, b. Forces on the gate, Failure modes include failure at hinge, failure at joint between rails and stiles, and racking

Prepare the opening

To reduce the chance of early failure, I want to carefully prepare both the hinge post and the latch post before hanging the new gate. First, ensure the posts are stable and plumb (Fig 2a). Even if the post does not wobble, check if it is attached securely to the fence rails. Remove any nails used to attach rails to the post and replace them with a combination of urethane glue and corrosion resistant lag screws (Fig 2b) to stabilize them. If needed, add pressure-treated 2×4 lumber as blocking to support the gate hinges and latch. If the post is near a building wall, use an angle bracket to anchor the post (Fig 2c).

CheckPlumb LagScrews

AnchorPost

Figure 2 a, b, c. Check for plumb, Replace nails with lag screws, Anchor post to wall

Make the frame

There are three common options for making a gate frame. The stiles can be full height, the rails can be full-width, or the corners can be mitered (Fig 3a). Once screwed together, the gate needs support to prevent it from sagging. You can use either pressure-treated lumber to make an angled brace to take compression load or a corrosion resistant cable tightened with a turnbuckle to take tension load (Fig 3b).

The frame of the gate should be made of pressure-treated lumber. To ensure stability, use pocket screws, not nails, to hold the gate frame together. First, drill the pocket screw holes using a jig (Fig 3c). Before installing the screws, measure the diagonals to ensure the frame is square (Fig 3d). I used a cable to support the load (Fig 3e).

Finally, if possible, cut any holes, mortises, or notches needed for the latch hardware now. My gate latch requires a single notch (Fig 3f). More on installing the latch later.

GateFrameOptions GateSupportOptions

DrillPocektHoles CheckDiagonals

AddCable CutLatchMortise

Figure 3a, b, c, d, e, f. Gate frame options (Full-height stiles, Full-width rails, Mitered corners), Support options (Brace, Cable), Drilling pocket screws, Measure the diagonals to ensure square, Add cable, Cut a notch for the latch

Prepare and attach the pickets

The cedar pickets at the store are very rough and not very attractive and need to be cleaned up. I use a random orbit sander to smooth the faces (Fig 4a). Then I use a block plane to smooth the sides (Fig 4b) and to chamfer the edges (Fig 4c). Once all the pickets are ready, use corrosion resistant screws to attach them to the gate frame. I start from the hinge side and align the first picket flush to the edge. Then I insert spacers (pieces of cardboard folded in half) and attach the next picket (Fig 4d). I continue until until only 2 pickets remain. I leave them off. I will attach them after the gate is hung.

If possible, attach the hinges now. Lay the hinges on the gate, place a straight edge (I use a loose picket) on top of the hinges to align them, and screw the hinges into the frame (Fig 4e).

At this point, the gate is ready to stain and varnish, but I did not do this.

SandPickets PlanePickets

EaseEdges AttachPickets

AttachHinges

Figure 4a, b, c, d, e. Sand the faces, Plane the sides, Chamfer the edges, Screw the pickets to the frame, Attach the hinges

Hang the gate

I am going the install this gate by myself. To hold it in place temporarily while I screw in the hinges, I make a shim. Place scrap wood (I used pickets from the old gate) at the base of the gate opening and ensure they are level and exactly at the height you want the bottom of the gate. Push dirt around as needed (Fig 5a). Rest the gate on top of the shim, ensure it is plumb, and screw the hinges to the post (Fig 5b). Remove the shim and test that the gate is level, swings freely, and does not bind.

There are three pickets left to install, one on the latch post and two on the gate itself. Measure the width needed to be covered by these three pickets, subtract the width of two spacers. Now divide by three. That will be the width of each picket. Rip the pickets to the correct width (Fig 5c). Use a block plane to joint the pickets (Fig 5d). Attach one picket to the latch post (Fig 5e) and the other two to the gate (Fig 5f). The picket on the gate may overlap the post. This is fine.

TemporaryShim AttachGate

RipPickets FinalMeasure

LastPicketsDetail LastPicketsDetail2

Figure 5a, b, c, d, e, f. A temporary base to hold the gate, Gate is hung, Rip the final pickets to width, Finish with block plane, Attach one picket on latch post, Attach two pickets to gate

Install the latch

I use a low-profile 2-way latch by Fenix. Unfortunately, there is a design flaw in the spring action. The latch bar will bind unless the hole for it in the latch handle is cut slightly larger and at an angle so that the bottom of the hole is wider than the top. I mark the outline for the larger hole using a red marker (Fig 6a) and use a file to enlarge the hole. I cut notches in the pickets in the gate to allow the latch handle through (no photo).

In another design flaw, the screws that come with the Fenix latch are too short to securely attach the latch handle to the gate. I pick two 5mm x 60mm (#8 x 2-1/2") corrosion resistant deck screws, paint the heads black, and use them to attach the latch handle to the gate. I attach the latch keep to the post and adjust its height until the latch opens and shuts smoothly. The gate is done (Fig 6b).

MarkHandle 

NorthGateOutside

Figure 6a, b. Modifying the latch hardware, The finished north gate