to increase the direct-to-diffuse ratio, meaning the bell sound - to - traffic noise in your application, perhaps the longer KMR82 will be even better suited. As even shotgun mics can give you only a certain amount of directivity and off-axis attenuation, moving closer to the sound source would be the second control parameter.
Then, if you're aiming at stereo reproduction, adding a figure-8 on top, for an MS configuration, would yield a controllable stereo spread.
Best regards, Martin Schneider / Neumann Mic. Development