It's low-cost but still a favorite...

The transparent roof on the 1955 Ford Crown Victoria (often called the "Glass Top" or mistakenly the "Skyliner") was made of a blue-green tinted, 1/4-inch thick, molded acrylic-plastic (similar to Plexiglas).

While the material itself was designed to be unaffected by heat, cold, or moisture and could be cleaned and polished to remove scratches, the primary issue associated with the transparent roof was not material damage from the sun, but rather the excessive heat build-up inside the cabin.

Key points regarding the transparent roof:

• Material: It was acrylic-plastic, not glass, and was tinted to theoretically filter out 60% of the sun's heat rays and 72% of the glare.

• Heat Issue: Despite the tint, the car was known to get unbearably hot on warm, sunny days, especially in the Southwest. This thermal discomfort was considered a major flaw and a reason the option was discontinued after only a few years.

• Mitigation: To help combat the heat and glare, Ford included an interior pull-out, adjustable "aluminized nylon" sunshade curtain that zippered in place.

• Durability: The material was generally durable for its time. Surviving examples today often have intact transparent roofs, though they may have been replaced during restoration (as acrylic can degrade or yellow over many decades, or be scratched).

So, while the roof material was relatively durable against sun-induced damage like cracking or warping, the effect of the sun (heat transmission) on the passengers was a significant problem.

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