Lombada vs. quebra-molas vs. lomba
While lombada, quebra-molas, and lomba all refer to a raised ridge on a road designed to slow down traffic, the difference lies almost entirely in regional usage and formality. Lombada and quebra-molas are the main terms in Brazil, distinguishing themselves by state and register, while lomba is the term used in European Portuguese.
Lombada
B1This is the technical and official term used in Brazilian traffic laws. While understood nationwide, it is the dominant word in everyday speech in the state of São Paulo and parts of southern Brazil. It sounds slightly more formal than its counterpart.
A prefeitura decidiu instalar uma lombada na frente da escola.
(The city hall decided to install a speed bump in front of the school.)
Você deve reduzir a marcha ao se aproximar da lombada eletrônica.
(You must shift down when approaching the electronic speed bump.)
Placas amarelas avisam que há uma lombada a 50 metros.
(Yellow signs warn that there is a speed bump 50 meters ahead.)
Quebra-molas
B2This is the most popular term in the vast majority of Brazilian states (such as Rio de Janeiro, Minas Gerais, and the Northeast region). It is a descriptive compound word literally meaning spring-breaker, referring to the car's suspension. It is widely accepted but considered less technical than lombada.
Passei muito rápido no quebra-molas e o carro pulou.
(I went over the speed bump too fast and the car jumped.)
Essa rua está cheia de buracos e quebra-molas sem pintura.
(This street is full of potholes and unpainted speed bumps.)
O motorista freou bruscamente ao ver o quebra-molas.
(The driver braked suddenly upon seeing the speed bump.)
Lomba
B2This term is used specifically in European Portuguese (Portugal). Travelers should be careful, because in Brazil, lomba generally means a steep hill or a slope, not a device to slow you down. In Portugal, however, it is the standard word for speed bump.
Em Portugal, os condutores reduzem a velocidade antes da lomba.
(In Portugal, drivers reduce speed before the speed bump.)
A estrada tem uma lomba perigosa logo após a curva.
(The road has a dangerous speed bump right after the curve.)
Construíram uma lomba para aumentar a segurança dos peões.
(They built a speed bump to increase safety for pedestrians.)
Summary
To sound natural, use lombada if you are in São Paulo or reading official Brazilian traffic signs. Use quebra-molas for informal conversations in most other parts of Brazil. Only use lomba to mean speed bump if you are in Portugal; otherwise, Brazilians will think you are talking about a hill.