Diokno Highway

The Diokno Highway, also known as Payapa Road and formerly as Tagaytay-Junction–Calaca-Lemery Road, is a 20.064 km, two-lane, secondary road in Batangas that connects the city of Calaca, near its border with Nasugbu and Alfonso, Cavite, and the municipality of Lemery. It connects southern Cavite and Batangas.

The highway is apparently named after Ramón Diokno, a native of Taal, Batangas who served as a representative for Batangas, senator and Supreme Court associate justice.

Route description
Diokno Highway starts at its intersection with Tagaytay–Nasugbu Road in Calaca, near the provincial boundary of Batangas and Cavite. Starting from near the foot of Mount Batulao, it runs through the mountainous terrain on the western edge of the Taal Volcano Natural Park, traversing especially Payapa Ilaya and Payapa Ibaba, barangays in Lemery to where its alternate name, Payapa Road, apparently derived its name from. It terminates at Palico–Balayan–Batangas Road in Lemery at the south.

History
The origin of the highway could be traced back to 1945, when the US Army Corps of Engineers built a “dusty, twisting, narrow” road between Mount Batulao and Lemery as the shorter route relative to Route 17, which connected Imus and Batangas via Palico in Tuy and includes the present-day Aguinaldo Highway, Tagaytay–Nasugbu Road and Palico–Balayan–Batangas Road. According to Major Edward M. Flanagan Jr. in his 1948 book, this road was called the Shorty Ridge Road, which likely refers the present-day Diokno Highway.

A portion of the highway was affected by a landslide caused by Typhoon Melor (Nona) in December 2015; fortunately, the entire stretch was open to traffic as of December 17. In August 2016, a 100 m section of the highway in Calaca was closed to traffic due to road slip and collapsed slope protection following the continuous heavy rains in the area. As a result, the Diokno Bridge was reconstructed beginning in the first quarter of 2017. The reconstructed bridge was inaugurated on November 13, 2018. The highway was also affected by the January 2020 Taal Volcano eruption, resulting to poor visibility on the highway and damage worth ₱41.62 million.