HOUSTON I-45 Parkway + Tunnel

 
Expansion of Highways Is NOT A Long Term Solution
Not exclusive to I-45, history shows that expanding highways is not a solution to congestion. It provides a disincentive toward development and use of other transportation alterantives/modes.

From the historic background of I-45 page, it is shown that I-45 was first constructed in the 1960's, then expanded to the current configuration in the 1980's, and it is now in the planning process of reconstruction. It is important to note that this 20-year reconstruction cycle is very typical in the expansion of highways. According to TxDOT's analysis the proposed expansion of I-45 will not solve long-term congestion. In fact, TxDOT analysis indicates that peak hours speeds after the expansion will improve by 1 to 3 MPH (see table below). Again, this is not typical to I-45 but to most highways.

Comparison of Existing vs. 2025 Congestion*
2003 - 9 Lanes
Volume
V/C
LOS
Peak Speed
IH 10 to IH 610
257,000
1.18
E
34 MPH
IH 610 to Beltway 8
317,000
1.46
E
27 MPH
2025 - 12 Lanes
Volume
V/C
LOS
Peak Speed
IH 10 to IH 610
250,648
1.15
E
35 MPH
IH 610 to Beltway 8
295,320
1.36
E
30 MPH
*Data Source: TxDOT I-45 Study – Exhibit ES.8
There are some traffic engineering concepts and data included in the above table that need explanation.
1. Traffic volumes from 2003 to 2025 do not increase but actually decrease in number. This is probably because the number of existing lanes (8) and the number of "free" lanes on TxDOT's proposed expansion are the same (8 lanes). Thus the increase of traffic between 2003 and 2025 is assigned to the proposed four "managed" lanes. The cross section below shows the proposed lane configuration of eight "free" lanes and four "managed" lanes.
2. V/C is a level of measurement for volume over capacity. A V/C greater than 1 means that the highway is over its capacity. This V/C is related to a Level of Service or LOS. In engineering term a LOS ranges from "A" to "F." An acceptable LOS is "C" or "D" although a LOS of "E" during peak hours could be acceptable. As shown by the table above the LOS of "E" does not change between 2003 and 2025.
3. The V/C and LOS are related to traffic speeds. In this case it is determined that current conditions and future conditions will have about the same peak hour speed.
4. So, why are the managed lanes not included? Perhaps it should be left to TxDOT to answer this question. However, it should be noted that currently METRO has the use of the one reversible "HOV" lane and its 2025 plan calls for having two HOV lanes. Then maybe the concept is for METRO to finance the HOV expansion from one to two lanes. The additional two lanes of the proposed four "managed" lanes are likely not to have funding sources and/or TxDOT may foresee partnering with the Harris County Toll Road Authority for funding and managing these "managed" lanes.
 
The reconstruction/expansion of I-45 primarily addresses the needs for: replacing the aging infrastructure, improving lane configuration, and updating facility to current standards (improve safety). However, TxDOT plans to take advantage of the opportunity to add capacity to the I-45 corridor with the addion of managed lanes.

There is one particular challenge in TxDOT's expansion of I-45. TxDOT's current proposal to expand I-45 north of I-10 from 9 to 12 lanes (not including service roads) offers no soulition forn continuation of the additional lanes south of I-10. The existing HOV lane south of I-10 ends on Washington Avenue near the Aquarium. Does TxDOT plan to extend the additional "managed" lanes into downtown? If not, TxDOT will have to consider expanding the Pierce Elevated. Expansion of the Pierce Elevated presents various challenges, one of which is no available right-of-way.

View of Pierce Elevated - How to expand it?
Rxpansion of Houston highways with undetermined extension beyond the 610 Loop is not new to TxDOT. Similar action is being undertaking in the expansion of I-10, US-290 and the Hempstead toll road. These new highway expansions do not extend south of the 610 Loop. So, how does TxDOT plan to manage added traffic? Could a part of the solution be TxDOT's current plan to build continuous service roads along I-10 from the 610 Loop in the west to I-45.
It is necessary to shift our thinking to long-term and envision the future of transportation in the urban core of Houston. What will it be like if all highways are continuously expanding from the suburbs to downtown? It is already known that expansion of highways DOES NOT solve traffic congestion long-term. What does TxDOT propose doing with I-45 after 2025?
It must be noted that the indiscriminate expansion of highways is not and must not be solely be attributed to TxDOT. TxDOT is only responsible for construction of highways and roadways. TxDOT cannot (by law) provide high capacity transit service. METRO is the responsible entity in the Houston region designated to provide transit solutions; however, METRO has been ineffective in developing a long-term plan (METRO Solutions) that will provide high capacity transit to the Houston region, leaving to TxDOT and the Harris County Toll Road Authority the responsibility for providing regional mobility. With this lack of transit leadership the Houston region has only one option - THE EXPANSION OF HIGHWAYS.