Preparation of Design Guidelines for Deep Underground Highways, "Enhancing Safety"

Revision of Design Guidelines in December... Creating a Safe and Comfortable Environment for Underground Expressway Use

[Asia Economy Reporter Cha Wanyong] Design guidelines for underground expressways constructed at great depths (more than 40m underground) will be established. These guidelines provide comprehensive and detailed standards for ventilation, disaster prevention, lighting, and safety facilities, with installation criteria strengthened compared to existing underground roads.

On the 16th, the Ministry of Land, Infrastructure and Transport announced that ahead of the full-scale promotion of the deep underground (more than 40m underground) expressway projects on the Gyeongin and Gyeongbu Expressways, it will revise the "Urban Area Underground Road Design Guidelines" applicable to underground roads designed for speeds of 100km/h. The revision draft will undergo consultation with related agencies from November 17 and is scheduled to be finalized in December.

Key revisions include stipulating a minimum tunnel height of 3.5m (previously 3m). This considers that most fire trucks, water tank trucks, and ambulances dispatched during fires have heights between 3m and 3.5m. Additionally, to prepare for situations requiring emergency passage of rescue vehicles when a vehicle breaks down or an accident occurs inside the tunnel, the right shoulder width will be increased to 2.5m (previously 2m).

Road alignment standards to improve driving safety will also be strengthened. Considering drivers' limited visibility caused by tunnel walls or internal facilities when driving through curves, the minimum horizontal curve radius standard has been increased (for 100km/h, from 460m to 1525m). The maximum slope of connecting roads will be reduced (from 12% to 7%) to enhance stability.

Disaster prevention facility installation standards to prepare for floods and fires have also been established. Drainage facilities for underground expressways will be designed considering rainfall with a minimum 100-year return period (previously 50 years), and adjusted upward to reflect regional rainfall characteristics.

At the ground entrances to underground roads, flood prevention facilities such as floodgates and waterproof doors will be installed to prevent flooding caused by heavy rain, and flood risk will be re-evaluated every five years.

In case of fire, a concentrated smoke extraction method will be prioritized to minimize smoke spread inside the tunnel, and the spacing between ventilation shafts will not exceed 5km to ensure smooth smoke discharge.

Additionally, to address user inconvenience caused by poor GPS reception inside tunnels, plans for installing GPS systems within underground tunnels have been proposed. Standards for attention alert facilities such as lighting and wall designs to prevent driver fatigue and drowsiness during long drives, as well as standards for installing Variable Message Signs (VMS) to guide tunnel exit locations, have also been established.

Lee Yongwook, Director of the Road Bureau at the Ministry of Land, Infrastructure and Transport, stated, "Through this guideline revision, the currently underway deep underground expressways such as Gyeongin and Gyeongbu will function as optimal urban underground roads that guarantee public traffic safety and driving security."

This content was produced with the assistance of AI translation services.