Need help with complicated route on Jalan Sultan Ismail, Kuala Lumpur

Posted by marche_ck on 8/26/2023

Summary of the situation

Current mapping is inadequate. I have some idea how to make it better, but I am not so sure just yet.

Southern junction

Top-right side road is a contra flow road. I had experimented by adding a diagonal access road from the south to the contra flow road, plus restrictions, to present a more intuitive navigation experience for users.

Signboard depicting contra flow. Own photo, GPS tagged

Southern point changeset

Why the diagonal access road? Consider the 2 situation below

1)Without diagonal access road. At first glance it looks like a pathfinder glitch.

Contra flow nav without diagonal access road

2)With diagonal access road. Far more natural.

Contra flow nav with diagonal access road

I think the addition of this diagonal access road improves user experience? It is far more easier to understand for navigation users, eliminating the need to consider whether 1 is a software glitch.

But whether is this “proper”, or are there any better ways to do this, I have no idea. Appreciate community input.

Northern junction

This is going to be long so go get a coffee☕

The picture above roughly describes how the main traffic here flows. As you can see, this is not a typical H shaped crossroad.

1. The 2 roads at the north forms a fork

Actual traffic, facing north. Own photo, GPS tagged

First, take a look at the photo above. “Giordano” below the billboard on the left is this shop as reference.

What I mean by the roads form a fork is how the road on the right, usually carrying opposing traffic, is actually carrying onwards traffic. But to a different destination. These are not multiple lanes of the same road separated by a median.

In Changeset #138139242 I tried to reflect this by experimenting with a “Y” shaped fork layout, resulting in a “pinched junction”, but the change was reverted by LakeArendsee due to conflicting information on this area.

Clarification of mixed information

First, road markings does suggest this traffic flow is allowed. I had returned to the same area and confirmed this is true

Feedback from LakeArendsee

My own photo of the road marking, GPS tagged

But there is the existence of this sign. Pedestrian bridge as reference.

Feedback from LakeArendsee. Shifting to road on the right not allowed.

The sign has since been removed.

Restriction sign removed. Own photo, GPS tagged

The question

The traffic flow is confirmed, but how to best reflect this? Looking back, the “Y” approach is not the best either. I am thinking of a “K” shaped layout, but yeah, community input needed.

2. Bottom right road is a contra flow lane

Right road is part of contra flow stretch from southern junction

Remember the contra flow road from the southern junction? The contra flow stretch continues and ends at this northern junction.

Normal hours traffic

Contra flow hours traffic

During contra flow hours, vehicles will have access to the top-right road, but not the top-left one. This adds a layer of complexity to mapping.

3. U turn blocked during contra flow hours

Notice in the photo of the road marking, there is also provision for making a U turn. But during contra flow hours, due to incoming traffic, this is no longer possible.

This further complicates the mapping problem.

The idea

I am thinking of using mainly a “K” shaped layout for the fork, with all others put in with conditional restriction during contra flow hours.

But, as you can see, the layout will be quite unusual. It is intuitive, reflects the real traffic pattern, but unusual.

Do you guys think this is a good idea? Or are there any other better options?