The following material is taken from the Devil's Slide Final Supplemental Environmental Impact Statement / Environmental Impact Report, prepared by the California Department of Transportation, June 1995.

The Montara Mountain Free Press has scanned and converted this material to text format for public consumption, and takes the responsibility for any inaccuracies that occurred in the conversion process. We would appreciate any corrections you might send our way at

Cover sheet (66K)

A tunnel alternative was considered and rejected as part of the CEQA/NEPA environmental review Process in 1986. The U. S. District Court subsequently determined that the treatment of alternatives in the 1986 FEIS was proper. Although only noise-related issues were addressed in the 1995 Draft SEIS, comments were received indicating a tunnel alternative would avoid project noise impacts. Several comments requested investigation of the tunnel option. This issue has been reviewed, and it is determined that the tunnel is not a reasonable alternative because of its inconsistency with Current Planning Policies, the lack of funding, and various safety and cost issues. These are discussed further in the following responses:

9.a) Planning Inconsistency

The proposed bypass has been certified by the State Coastal Commission as consistent with the policies and objectives of the California Coastal Management Program. A new tunnel alternative would require that the project meet federal consistency program regulations and a new or amended consistency certification be submitted to the Coastal Commission for concurrence.

The proposed bypass is included in the current programming and planning documents of the Metropolitan Transportation Commission's (MTC) 1994 Federal Transportation Improvement Program (TIP) and in the MTC 1994 Regional Transportation Plan (RTP). The project has complied with MTC's Intergovernmental Review (IGR) process.

The proposed bypass project is also Consistent with the Local Coastal Program Element of the County of San Mateo's General Plan. In addition, the cities of Pacifica and Half Moon Ray have formally endorsed the proposed bypass project. Recently, on April 4, 1995, the San Mateo County Roard of Supervisors reaffirmed its support for the propoSed bypass project by voting against a proposal to request that Caltrans further consider other alternative proposals such as a new tunnel.

9.b) Funding

In 1984, Congress provided special emergency relief (ER) funds in Public Law 98-229. These special funds were available for obligation until September 30, 1986. Under Title 23, United States Code, which includes the ER program, funds cannot be obligated for a project in general. Funds can only be obligated by approval of contract documents for a specific project alternative. In September 1986, special ER funds were obligated for the Martini Creek bypass alternative when the federal government approved the contract documents for constructing the bypass. Under the law, set forth in Title 23, these funds cannot now be transferred from the Martini Creek bypass to another project alternative since the obligation deadline has passed.

Furthermore, if the bypass is not constructed, the current obligation of the federal government will end and the obligated funds will lapse. There is no identified source of funding for a tunnel alternative.

9.c) Design Considerations, Safety, and Cost

The design of any highway including tunnels must reflect safety as a major consideration. Various factors such as traffic volume, speed, horizontal and vertical alignment, sight distance and clearance, and traffic composition (including bicyclists) are considered and incorporated into the design to provide the appropriate number of traffic lanes, adequate lane and shoulder widths, a recovery or refuge area, and traffic control systems. Tunnels require the additional consideration of an appropriate ventilation system, lighting, and emergency vehicle access. The potential for catastrophic accidents within the confined space inherent with a long tunnel is a very serious concern which must be addressed in the design of a highway tunnel.

For a long tunnel, safety is a major concern for the traveling public as well as for maintenance workers, who provide necessary service and maintenance operations on a 24-hour basis. Access for emergency vehicles and the possibility of catastrophic events that could completely close a tunnel must be considered in developing an appropriate cross sectional width for a long single bore tunnel. In addition, consideration for bicycle access needs to be included since Route 1 is a conventional highway and is on the Pacific Coast Bike Route.

Considering the safety issues and safe access for bicyclists, the minimum acceptable cross section for a long, single bore tunnel is 19.8m (66 feet) wide. This section consists of one 3.6m (12-foot) travel lane with a 2.4m (8-foot) shoulder in each direction, a 1.5m (5-foot) bike lane in each direction with a 0.3m (one-foot) offset between the shoulder and the bike lane for placement of delineators, a 1.2m (4-foot) walkway in each direction for maintenance and pedestrian use, plus a 1.8m (6-foot) median separation. If an alternate route for bicyclists is provided and bicyclists are prohibited in the tunnel, the cross section width could be reduced to 17.4m (58 feet). This cross section eliminates the 1.5m (5-foot) bicycle lane and 0.3m (one-foot) offset between the shoulder and the bike lane in both directions, and provides for a 3m (10 foot) shoulder for emergency access. See attached typical cross sections.

A 14m (46-foot) wide tunnel is not acceptable because it does not meet the need for a safe walkway area for the Caltrans maintenance workers, or the public in case of an emergency, and does not provide 10-foot shoulders to more adequately allow space for disabled vehicles in a confined area. It also does not meet the need for safe bicycle access if such access can not be provided on an alternate route.

Recent Caltrans studies indicate that the estimated construction cost of a 19.8m (66-foot) wide, 1,356m (4,430-foot) long tunnel would be $126.8 million. This estimate only includes the cost of construction, and does not take into account other costs associated with building and maintaining such a tunnel. All construction cost estimates must account for the potential for structurally poor material in the San Pedro mountain. A detailed geologic investigation would have to be accomplished before the alignment and cross section of a tunnel could be finalized. Based on the preliminary cost estimates, a double bore tunnel compares favorably with a single bore 19.8m (66-foot) tunnel.

Numerous comments claimed that construction of a single bore tunnel through San Pedro mountain would be less expensive than the cost of building the bypass, thus making the tunnel a more reasonable alternative. It was stated that the construction cost of a 1,356m (4,430-foot) long, 14m (46-foot) wide tunnel would be approximately $60 million. Caltrans estimates that the construction cost of such a tunnel alone would be $88.6 million, which results in a total project cost of $124 to 129 million using 2 to 4 years construction delay cost, plus annual maintenance cost.

The Cost Analysis Table on the next page applies the same cost criteria for design, maintenance, construction engineering and construction delay used for the proposed bypass project to allow for a more equitable cost comparison of the two proposals, and to give a better representation of the actual cost for such a project.

9.d) Other Tunnel Considerations and Responses

Tunnels present other safety hazards that do not occur on the open highway. It has been noted that with long tunnels, the contrast in lighting at the entrances and exits of the tunnel results in a distinct reduction in speed, thereby creating a potential for congestion and accidents. Drivers generally experience some difficulty in quickly adjusting to the change in lighting conditions. Consequently, a variable lighting system would be required throughout the tunnel to facilitate tft@ driver's adjustment to the variation in the lighting throughout the day and night periods.

In addition to lighting, tunnels must have supporting electrical, mechanical, ventilation and air quality control system, telephone call boxes and surveillance devices. A failure of any of these devices could conceivably contribute to accidents or delayed response to accidents.

Devil's Slide Bypass & Tunnel Option Cost Analysis
                         Devil's Slide      Single bore   Single bore     Single bore   Double bore
                         Bypass Project     17.4 Meters   19.8 Meters     14 Meters     11 Meters ea.
                                            (58 Feet)     (66 Feet)       (46 Feet)     (36 Feet ea.)
Construction cost        $69,030,000        $94,300,000  $126,800,000     $88,600,000   $123,800,000

Design cost               $3,451,500        $18,860,000   $25,360,000     $17,720,000    $24,760,000
(20% of Const. Cost)*

Construction Engineering $10,354,500        $14,145,000   $19,020,000     $13,290,000    $18,570,000
(15% of Const. Cost) **

Construction Delay     Not Applicable        $4,774,000    $6,419,000      $4,485,000     $6,267,000
(2-Years) ***

Construction Delay     Not Applicable        $9,790,000   $13,163,000      $9,198,000    $12,852,000
(4-Years) ***

Total cost               $82,836,000     Not Applicable Not Applicable Not Applicable Not Applicable
with no delay

Total cost with       Not Applicable       $132,079,000  $177,599,000    $124,095,000   $173,397,000
2-years delay

Total Cost with       Not Applicable       $137,095,000  $184,343,000    $128,808,000   $179,982,000
4-years delay

Annual maintenance cost     $340,000         $1,210,000    $1,210,000      $1,210,000     $2,260,000
(see note)

* Use 20% of Construction cost for all alternatives which do not leave any design work done, and 5% for updating the current Bypass Design.
** Use 15% of construction cost for all alternatives.
*** Construction Delay Cost based on cost increase using 2.5% inflation rate for 2-4 Years delay as compared to the proposed Bypass. The tunnel development timeline would require time for acquiring federal funding and planning consistency determination, obtaining proper permits, geological exploration, finalizing the environmental document, design and construction.

Note: The approximate average annual maintenance cost per mile, for the tunnels in the Bay Area, based on data for the Caldecott tunnel, Posey and Webster tube is $1,250,000. The Eishenhower tunnel on I-70 in Colorado, has an annual maintenance cost of approximately $1,270,000 per mile. Using the local Bay area tunnel information, the expected annual maintenance cost for the proposed 1,356 meter (4,450-foot) long tunnel alone would be $1,050,000. Historically, CaItrans has spent an average of $28,000 per kilometer ($45,000 per mile) annually for the maintenance of the 8Km (5 miles) of Route 1 between pest miles 36.0 and 41.0. For a tunnel option, the average annual maintenance cost of the remainder of the existing highway from Linda Mar Boulevard to the north of the current proposed tunnel, and from south end of the tunnel to the Chart House (5.6 Km @ $28,000 per km (3.5 miles @ $45,000 per mile)) is about $160,000. This results in a total of $1,210,000 annually for the maintenance of a single bore tunnel Option, Since the annual maintenance cost of the Bypass is estimated at $340,000, the annual maintenance cost of the single bore tunnel option will be $870,000 more than the Bypass project. Capitalizing this additional cost, in perpetuity, at a rate of 6.5% based on T-bond and accounting for Cost Of Living Adjustment (COLA) of 2.5% per year, the present value of this additional cost would be $21,750,000.

Tunnel cost estimates in the table above, do not include the cost of providing a separate bike trail, except for the 20m (66 foot) wide tunnel, which does accommodate bike access.

The 14m (46 foot) wide tunnel consists of two 3.6m (12 foot) lanes, a 1.2m (6 foot) median separation, end two 2.4m (8 foot) shoulders.

Another important safety consideration in tunnel design is the provision of a quick and easy escape route after an accident. The only escape route in a long, single bore tunnel is to exit the tunnel itself at either end. If an accident were to occur in the center of the 1 ,356m (4,430-foot) tunnel proposed by tunnel advocates, the only available escape routes would be 678m (2,225 feet) away at each end. It is also more difficult to respond to accidents which occur within a tunnel, by the very nature of its confinement. This confinement precludes the immediate utilization of air medivac until the injured are first removed from within the tunnel.

A comment was made stating that a two lane, bi-directional, long tunnel is safer than an open highway. There are no local, two-lane, bidirectional tunnels comparable to the long tunnel currently proposed by tunnel advocates. An evaluation of the accident data for several one directional tunnels within the Bay Area does not provide any evidence to support the statement that a tunnel is safer than an open highway. As indicated above, the primary safety concern within a long tunnel is the potential severity of the accidents as a result of its confined space. One example is the catastrophic accident which occurred in 1982 on Contra Costa Route 24. This involved a collision between a gasoline tanker and several vehicles in one of the three bores of the Caldecott tunnel. The tanker caught fire and exploded in the tunnel. There were seven (7) fatalities in that accident and the affected tunnel bore was closed for several weeks for emergency repairs. During this period, traffic service was provided by the other two tunnel bores which were not affected by this accident. Even if flammable fuel tanker trucks were prohibited in the tunnel, vehicle fuel tanks could still erupt and an accident could become more deadly because of tunnel confinement.

If the Sierra Club's statement regarding FHWA's findings on tunnel safety statistics is in reference to the report number FHWA/RD-83/032, dated June 1983 titled "Prevention and Control of Highway Tunnel Fires", then the statement is misleading and does not present the entire picture. This report only addresses the fire statistics in the tunnel. The report did not discuss traffic accidents in the tunnel in general, but rather studied accidents and the resulting fires and suggested fire prevention measures. As discussed earlier, accident history indicates a higher actual accident rate within local tunnels and their approaches than on a comparable highway. It should be emphasized that the contents of FHWA research reports do not necessarily reflect the official policy of the FHWA, and do not constitute a standard, specification, or regulation.

Several tunnels were identified and referenced in comments suggesting that the tunnel option was a solution to the Devil's Slide problem. Caltrans has obtained the following information on these tunnel projects referenced:

The highway project in Oregon referred to in the Sierra Club's letter has a length of approximately 335m (1,100 feet) with two 3.6m (12foot) lanes, a 2.4m (8-foot) and a 1.8m (6-foot) shoulder. This project, which was planned for Route 38, south of Eugene, between Drain and Elkton, did not include any federal funding or require any federal approvals. Although this project was designed, it was never built due to a funding shortage. This tunnel project was intended as replacement of an existing tunnel in need of repair. The projected traffic volume on Route 38 for year 2013 was estimated at 3415 Average Daily Traffic (ADT). Traffic volume on Route 1 at Devil's Slide is currently between 10,000 to 14,000 ADT.

Other tunnels identified in the comment letters included several in South Dakota. There are presently seven (7) tunnels on South Dakota's highway system, all of which are located in the Black Hills in the western part of the State. These tunnels range from 15 to 91m (50 feet to 300 feet) in length, and 2.6 to 12.8m (8 feet, 8 inches to 42 feet) in width and have vertical clearances of 3.3 to 4.4m (10 feet, 8 inches to 14 feet, 6 inches). All of these tunnels except the one that is 12.8m (42 feet) wide, provide two-way traffic taking turns in each direction. Traffic speeds in these tunnels are low and traffic control for the one direction at a time movement is accomplished with signage which reads "SOUND HORN". These signs are located at each approach. The 12.8m (42-foot) wide tunnel which is 24.3m (80 feet) long, has three lanes with two way traffic. In 1991, a study was prepared for the SDDOT to determine the feasibility of constructing the eighth tunnel in the Black Hills area. The feasibility study included four alternatives consisting of single bore, bi-directional tunnels and double bore, one directional tunnels 259 to 535m (850 to 1,820 feet) long. This project has not been constructed and is not in the SDDOT's five year construction plan.

The Eisenhower tunnel in Colorado is a two lane, two bore tunnel, constructed at a cost of approximately $250 million and opened to traffic in 1973. It is at an elevation of 3,353m (11,000 feet), with an eastbound tunnel length of 2,731m (8,960 feet) and a westbound tunnel length of 2,725m (8,939 feet). The average grade of the tunnel is 1.64% with the approaches leading into the tunnels at approximately 7% grade. The entire tunnel has a 5m (16-foot, 4-inch) vertical clearance, and a 7.9m (26-foot) width. There are 7 carbon monoxide analyzers in each tunnel with twenty-eight, 600 horse-power ventilation fans capable of moving 14,160 cubic meters (500,000 cubic feet) of fresh air. Fans are activated manually depending on the time of day and volume of traffic. There are also a total of 30 surveillance cameras for the operation of the tunnel.

The current annual maintenance and operations budget for this tunnel is $4.3 million. Aside from utilities and maintenance costs of operating the tunnel, this budget also covers the salary of 50 full-time employees involved in the day-to-day operation of the tunnel on a 24 hour-per-day basis. The maintenance crew owns its own fire equipment because assistance from the nearest town involves a twenty minute travel time. The emergency response units are located at both ends of the tunnels. I-70 at this location has an ADT of 22,000.

Although this tunnel was not intended for bi-directional operation, the increase in traffic demand during the ski season results in one of the tunnel bores being used as a bi-directional tunnel; this allows for three lanes in the direction of heavy traffic and one lane in the opposing traffic lane. Lane separation is provided by the placement of Air Spill Channelization Barricades (Cones) at 12m (40-foot) intervals. The normal speed limit of 80 km/h (50 mph) is reduced to 64 km/h (40 mph) when the reversible lane is in operation. The reversible lane for two way operation is used about 6 times a year for a period of 4-5 hours each time. Within the tunnel, there are lane control signs with a "Red X" and "Green Arrow". On bright days, drivers experience the "black hole effect". To remedy this, the intensity of the tunnel lighting system is adjusted.

In the case of the Eisenhower tunnel, there were no other feasible alternatives, resulting in the selection of the tunnel alternative as the preferred alternative.

In response to comments received, we recognize that design build contracting may result in some cost savings. However, we disagree with the claim that a $30 million cost savings can be realized by using design build contracting for a tunnel alternative.

In regards to comments and claims that the current Caltrans esrthwork cost for the bypass is underestimated and does not account for required blasting, Caltrans agrees that earthwork excavation which requires blasting is more expensive than earthwork that does not require any blasting. For the bypass project, Caltrans estimates that blasting may be needed for only 8% to 10% of the excavation. Review of the current earthwork estimate, including factoring in the potential blasting need, recognizing the large quantity of earthwork and unrestricted hauling conditions on this project, (there is no traffic handling cost since the proposed bypass is on a new alignment), confirms that the earthwork excavation cost is within the current cost estimates.

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