Entry no.49 - Highway 704 Extension
This update marks a return to the original concept I had for the CJ all those years ago: functional transportation improvements. You see Houston, we have a problem... While my region's highway network is already quite extensive, it turns out my constituents think much like Americans—you can never build enough freeways to satisfy them! In Pretoria, one of these issues exists in the Middle East Borough, where Lindin City is located.
Overview of the Problem
Below is a regional overview of the all the highways and interchanges seen so far. The main goal of the highway network is to efficiently funnel rush hour traffic to and from the Central Pretoria(where the Central Business District/CBD is located) from each of three boroughs; The North Point, Middle East(M.E.) and South Shore - Only the latter two are relevant in this location.
Traffic from the South Shore and Middle East Boroughs have three options to cross the large bay and river standing between them and Central Pretoria. These 3 options collectively provide 16 lanes of highway traffic. IRL, a single free-flowing highway lane is estimated to allow a little over 2,000 vehicles per hour(a range of 1,800 to 2,400 vehicles to pass per hour) this gives us a capacity of around 16,000 vehicles per hour, per direction in total. However, it's important to note that once congestion reaches 100% or more capacity decreases to around 1,500 vehicles per hour.
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In the overview above the westernmost crossing is the six-lane Cisco Bay Bridge, connecting Dresden and Calgon via Highway 702. Built in 1964, this bridge is always at 100% capacity and often higher approaching 110% to 120% during rush hours. When free-flowing, about 7,000 vehicles per hour can use the bridge in the peak direction. But when congestion exceeds 100% traffic starts to slow down reducing capacity to around 5,000 vehicles per hour and causing hour-long delays. It experiences this severe congestion because this bridge carries about 90% of the traffic from Dresden and the South Shore. In terms of real-world equivalents, it's comparable to the San Francisco–Oakland Bay Bridge or the George Washington Bridge in terms of regional importance.
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Next we have the six-lane Sky Bridge, which crosses the narrowest part of Cisco Bay via Highway 700. The current cable-stayed bridge, built in 1989, replaced a cantilever bridge built in 1937. Before Highway 704 was built and connected to Spaghetti Junction, this bridge operated at about 85% capacity with a traffic flow of about 5,500 vehicles per hour per direction, while handling about 70% of the traffic from the Middle East Borough and the remaining 10% of the traffic from Dresden and the South Shore.
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Lastly, the easternmost highway crossing is the four-lane Higgs Boson Bridge-what can I say, I like science! This bridge carries the eastern stub of Highway 705 over the Trueno River and rarely operates at over 50% capacity, averaging between 1,500–2,000 vehicles per hour in the peak direction. This low capacity factor is due to a major constraint: the eastern stub of Highway 705 lacks a direct interchange connection with Highway 700 in LC. Instead, it funnels traffic directly into the downtown area, which is perfect if that's your destination but not so much for drivers who want to go beyond there. These drivers must navigate multiple intersections and a low-capacity single-lane on-ramp that feeds traffic onto the northbound 700. Unfortunately no practical solution exists to fix this problem, an interchange at this location is prohibited since it's located in a dense neighborhood and would require the demolition of a large number of buildings to accommodate. While I do love my highways, that's a non-starter. This route is however also still useful for people who traveling through LC to connect with the western section of Highway 705 and heading to work in the large industries of Baycole(e.g. The Apotex Refinery).
This lack of a direct connection between the 705 and 700 wasn’t a huge problem since this traffic would not detour onto the 705 but instead just continue down the 709 and connect to the 700 in Cisco Bay instead and from there cross the Sky Bridge on its way north to Central Pretoria(path 1 on the street map below). However, the situation worsened after Highway 704 was built, which is ironic since that highway was constructed to alleviate congestion, though on a different part of the highway network—in the 700/707 joint section. The 704 provided a congestion-free alternative to the CBD and even though this was a much longer route for people travelling from the South Shore to get to the CBD, it was still a often a quicker alternative to being stuck on the perpetually crammed Cisco Bay Bridge. This increased the proportion of South Shore using the Sky Bridge from 10% to 25%, which brought that bridge's capacity to 100%.
The solution was simple - create an alternative connection to highway 700 & 704 from the 709 so as to take advantage of the spare capacity(about 2,000-2,500 vehicles per hour/direction) available on the underutilized bridge located there and divert traffic away from the route over the Sky Bridge. This new section of highway would designated as a southward extension of the 704 and turned Spaghetti Junction into a 5-way interchange;
The best and most cost-effective path was determined to be along the red dotted path seen on the local street map below. The land through which is entirely undeveloped resulting in very few NIMBY concerns and makes use of the existing highway bridge and interchange between the 705 & 709. An alternative and slightly more direct route along the purple dotted path was also considered, but this would require the construction of a new river crossing, new interchange and required some expropriation & demolition in Mayfield, all for very minimal time savings at a much higher cost- thus it was declined.
Synopsis from above;
1 - The long route that most traffic currently takes and has resulted in congestion on the 700 over the Sky Bridge and through LC due to increased traffic flow from Dresden(purple arrow) to the 704
2 - The short but less preferred route because it's such a go through Downtown LC (exactly where the #2 is on the map). Having so many extra cars cutting through the downtown area also creates an unsafe enjoinment for road users and pedestrians alike, a situation the current major of LC promised to rectify. Hence why he had no objects over building an entirely new stretch of highway in another part of the city.
3&4 - Additionally some traffic from the 709 also began to spill out onto local 2-lane streets and roads in an attempt to seek out alternative and less congested routes, which were never meant to be main thoroughfares.
Overview of the Project
Here's the end result beginning with an overhead shot of the entire extension and a high zoom shot of the area around northern entry point
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We'll follow that with by a series of close ups at various angles where the 704 branches off from Spaghetti Junction
The 707 turns north-east here with the NB lanes running under the 704, while the 704 continues eastward before curving south
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A 550-foot tall structure called the LC Hillsboro-Roads Transmission Tower overlooks the junction
While making this update realized I never released the updated HD-version of this particular BAT with the others a few years back. So for those of you who would like your own citizens to worriedly question; "just what is that thing really being used for...?" here is the updated version of this dark and nefarious looking hi-tech tower, heheh... 😁
Junctions in motion
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Tall sound walls are used to reduced the noise pollution coming off of the highway so that the residents of the Neighborhood of Rockcut can get some sleep
If you're wondering what that high-tech looking lot at the top of the last couple of images is, that would be the Hillsboro TS (Transmission Substation) which was originally featured all the way back in entry number 2! The substation and local area has undergone some changes since it was last seen on the CJ
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Moving on to the Duluth Road interchange which passes diagonally underneath. An embankment was built up on both sides of the road so that it stayed open while the highway was built
Further back we can see how dramatically the highway curves southward as it moves through the neighborhood of Rockcut
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These next couple of shot might be my favorite because of the "open" feel to them
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Messing with the angles a bit
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Back to some normal angle closeups, with an mmp focus
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Emerging from a tunnel underneath the 704 is the Fastraxx ME commuter train line. Previously I had this tunnel continue under the river in a tunnel but then I thought wouldn't it look do much more interesting to have it pop out here and go over it instead?
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That little single piece road tile I left there is the last remaining remnant of a road bridge over the river that previously existed in this spot
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Playing with the angles again
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Moving on to the next portion, overhead high zoom shot of the entire southern section of the extension
I think seeing the automata in motion really helps to get an idea of the changes in the elevation grade of the highway quite well. Straight down;
Looking North
Further back
Even further back still
"World's smallest interchange" merger of the 704 extension and the 705 stub, might need to upgrade this mini-interchange in the future if demand warrants it
The Lealand Sewage Treatment Plant is tucked in this little corner of the city as well
Taking a look down the river towards the rail bridge
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The "Butterfly interchange" between the 704/705 and 709
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Concluding the entry I some long & wide pano shots; South East view
North West view
The completion of the new extension was indeed a success and reduced the congestion over the Sky Bridge by transferring about 1500 to 2000 vehicles per hour in the peak direction to the bridge in LC instead. But who can say how long this will last for before the effects of urban sprawl rear their ugly head again.
This will likely be the last time I work on this city, a final few parting city-wide shots
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Sayonara L.C. it's been fun 👋
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