Bumper sticker

A bumper sticker is an adhesive label or sticker designed to be attached to the rear of a car or truck, often on the bumper. They are commonly sized at around 25.4 by 7.6 cm (10.0 by 3.0 in) and are typically made of PVC.

Bumper stickers serve various purposes, including personal expression, promotion, humor, or political activism. They encompass commercial, religious, secular, military, and sports-related themes, allowing individuals to showcase affiliations or support for various causes, regions, or groups. While they are widely used in the United States to display political support during elections, their prevalence is comparatively lower in countries like the United Kingdom.

Before the emergence of bumper stickers, advertising took various forms, including horsefly nets, metal or cardboard bumper signs, and window shield decals. The advancement of fluorescent inks during World War II and the accessibility of pressure-sensitive and adhesive materials in the post-war period played a significant role in the development and widespread adoption of bumper stickers.

Bumper stickers can be commercial, religious, secular, humorous, or in support of a sports team or other organization. They may promote or oppose a particular philosophical or political position. Or they may go a different route and show a funny cartoon or punchline. In some countries, such as the United States, bumper stickers are a popular way of showing support for a candidate for a government seat and become more common during election years. In others, such as the United Kingdom, they are rarely seen in any form.

One variety of bumper stickers is the country tag. This is typically used for cars crossing international borders, and is overseen by the United Nations as the Distinguishing Signs of Vehicles in International Traffic, being authorized by the UN's Geneva Convention on Road Traffic (1949) and Vienna Convention on Road Traffic (1968). Often the country code is displayed on the license plate itself.

These have (usually in the United States) been appropriated into tags indicating a country with which the driver affiliates, or more humorously to indicate things like a region (OBX), support for rabbit rescue groups (BUN), etc.

People who opt to exhibit their individuality through these decals may take part in more acts of road rage. Colorado State University social psychologist William Szlemko found that aggressive driving is linked to the number of markers a person has on their car, regardless of the messages portrayed.

Early bumper stickers had printed directions on the back removable liner for applying them to the bumper of a car. Due to the movement of the vehicle and changing weather conditions, the sticker needed to adhere well to the bumper surface.