AndreyT

Intersection of Mary and Homestead in Sunnyvale, near Homestead High School.

https://goo.gl/maps/K1FcDTYwwxvphmgFA


The markings seem to suggest that diagonal crossing is supposed to be allowed there. If so, what are the current rules for crossing such crosswalks? I inspected all corners of this intersection, and I couldn't see any special traffic control devices intended to control diagonal crosswalks. All stop lights, vehicular and pedestrian, are pointing in "regular" directions, i.e. they control "regular" crosswalks and traffic. How and when is one allowed to cross diagonally?

And if this intersection is not intended to be diagonally crossable, then what are those extra stripes doing there?

CliffordK

I would think if they were intended to be diagonal crosswalks, they would be better marked, and would indicate crosswalks across the entire street.



https://www.alpharetta.ga.us/governm...town-august-18

This article seems to have similar marking to what you're seeing.



https://www.signalsaz.com/articles/t...-safety-month/

So, it is officially called a "Pedestrian Scramble".

At least in the Alpharetta Georgia case, they seem to indicate that there is a special yellow push button that pedestrians can use to stop all traffic for the diagonal crossing.

If you go to that intersection, look for button activated crossings. And look at what happens during the signal cycles. Are all cars stopped at the same time?

DiabloScott

You know what's missing in this photo, are the lane markers for turning cars - drivers would have a more difficult time judging their line with the crosswalks all the way across than with the OP's photo - where you can see the turning lane guides.

zandoval 

Pretty simple really...

RUN!!!

CliffordK

Good point. However, I'm not sure I pay that much attention to lane markers when it is a single left turn lane. They're really only needed with two left turn lanes.

Head to the destination lane. Don't run into oncoming traffic.

Street marking can get pretty busy. One could do the lane guides with a thick yellow or red stripe that could even go across the top of the white Zebra. Or, rather than Zebras, do simple white outlines for the cross walks.

mschwett 

do the lights have an “all red” cycle inserted in the pattern, at which time all the pedestrian walk signals are green? that’s the way the many pedestrian scramble crossings in SF are designed. we don’t do the diagonal zebras though.

bikingshearer 

On Montgomery Street, there are separate cross-walk signals for diagonal crossing, which takes away most of the confusion. Without them, it would be an unholy mess.

The only problem are the illiterate or obtuse drivers who cannot or will not read and obey the "No Right Turn on Red" signs.

mschwett 

true, the chinatown ones have those also. but it’s just a regular walk/don’t walk thing rotated 45 degrees, i’m not sure how effective that would be at the scale of the sunnyvale intersection.

the only place i can recall seeing actual diagonal markings like the OP’s example is the new crossing at bridgeway in sausalito, which definitely has a separate control.

CliffordK

I wonder how many pedestrians get confused with controls, or simply just hit the stop everything button.

Separate curb cuts for diagonals may help.

I have one median separated bike path that inevitably getting off the path and onto the roadside bike lane to the left requires two cross walks. The diagonal would be nice, but I doubt the city will put one in. Already it has too complex of a traffic flow pattern, and cyclists are always considered an afterthought.

AndreyT

Some important details escaped my attention when I saw that intersection for the very first time.

Firstly, signs posted next to pedestrian "request crossing" buttons explicitly state that "scramble" mode is active for some period in the morning and in the afternoon. I presume that during these periods the intersection always uses "scramble" mode when it decides to allow pedestrian traffic.

Secondly, yes, there are dedicated diagonal pedestrian signals for diagonal crosswalks. I simply missed them previously. And yes, in "scramble" mode all pedestrian signals display "walk" signal (including the diagonal ones), while all vehicular signals become red.

AndreyT

Bizarre intersection... The posted morning scramble mode period ends at 9:15am.

And indeed, if you arrive at around 9:20am, diagonal crossing is no longer available, and the lights revert to regular mode of operation. However, if you press the button on the sidewalk box and wait for the pedestrian crossing light to turn green, the plain-language voice announcement that emanates from the box will still claim that the crossing operates in scramble mode! The voice announcement says something along the lines of "scramble mode in operation, all vehicular traffic lights are now red", which is not true. Apparently, the actual lights and the voice announcement device operate from a different clock or use different cut-off time for some reason (?). The lights stop using scramble mode, but the voice announcement device believes scramble is still active.

If I understand correctly, these voice announcements are there to improve safety for vision-impaired people. I don't know whether they actually rely on such devices, but making the lights and the voice operate out-of-sync achieves exactly the opposite...

cthenn

That's just weird that there's a scramble schedule where it actually ends. Seems very dangerous to have the diagonal striping yet not allow that movement, which could lead to confusion and even an accident. Especially if it's a first or second time using the intersection. What if you previously used it during the scramble phase when all lights were red, and the next time you use it, it's outside of the schedule, but don't realize it. Is the 20 extra seconds really affecting traffic? Also, the most congested time for cars is morning/afternoon, which seems to align with the scramble period. Weird.

We have a lot of these intersections in Walnut Creek, none of which have a schedule, and are the same scramble mode all day long.