A vehicle structure (100; 200) comprising a portion (102; 202) extending in a longitudinal direction , wherein the portion (102; 202) comprises a first member extending in the longitudinal direction , and a second member extending in the longitudinal direction , wherein the first member is configured to face an inside of a vehicle, wherein the second member is configured to face an outside of the vehicle, wherein each of the first and second members has a compartment extending in the longitudinal direction , each compartment having a bottom surface configured to face one of the inside and outside of the vehicle, wherein the first and second members are attached to one another such that the compartments and the first and second members form a substantially closed space , wherein the portion (102; 202) comprises one or more reinforcement members located in the substantially closed space , the reinforcement member extending in the longitudinal direction , wherein the reinforcement member has a first leg extending in a direction transverse to the longitudinal direction , wherein the reinforcement member has a second leg extending in a direction transverse to the longitudinal direction , wherein each leg has a foot extending in the longitudinal direction , wherein the foot of the first leg and the foot of the second leg are spaced apart from one another, wherein the first and second legs are joined in a head section , wherein the head section is corrugated and comprises corrugations, wherein the corrugations comprise ridges and grooves , wherein each ridge extends between the first leg and the second leg , and wherein each groove extends between the first leg and the second leg , characterised in that the first leg is located between the second leg and the bottom surface of the compartment of one of the first and second members while the second leg is located between the first leg and the bottom surface of the compartment of the other one of the first and second members . a first member extending in the longitudinal direction , and a second member extending in the longitudinal direction , wherein the first member is configured to face an inside of a vehicle, wherein the second member is configured to face an outside of the vehicle, wherein each of the first and second members has a compartment extending in the longitudinal direction , each compartment having a bottom surface configured to face one of the inside and outside of the vehicle, wherein the first and second members are attached to one another such that the compartments and the first and second members form a substantially closed space , wherein the portion (102; 202) comprises one or more reinforcement members located in the substantially closed space , the reinforcement member extending in the longitudinal direction , wherein the reinforcement member has a first leg extending in a direction transverse to the longitudinal direction , wherein the reinforcement member has a second leg extending in a direction transverse to the longitudinal direction , wherein each leg has a foot extending in the longitudinal direction , wherein the foot of the first leg and the foot of the second leg are spaced apart from one another, wherein the first and second legs are joined in a head section , wherein the head section is corrugated and comprises corrugations, wherein the corrugations comprise ridges and grooves , wherein each ridge extends between the first leg and the second leg , and wherein each groove extends between the first leg and the second leg , <EOS>