Modifiers matching road:

• major,
• busy,
• outdoor,
• narrow,
• straight,
• level,
• irregular,
• heavy,
• rough,
• off,
• real,
• public,
• paved,
• substandard,
• light,
• flat,
• big,
• down,

Simple categories matching flat:

• object,
• surface,
• tray,
• system,
• pan,
• region,
• article,
• paint,
• tube,
• fruit,
• textile,
• weapon,
• representation,
• material,
• item,
• fish,
• area,
• bread,
• component,
• stage,
• background,
• book,
• roof,
• brush,
• place,
• substrate,
• board,
• mineral,
• graphic,
• container,
• ware,
• accessory,
• wire,
• plan,
• metal,
• side,
• polygon,
• epithelium,
• support,
• ground,
• solid,
• cover,
• charge,
• panel,
• screen,
• marker,
• shape,
• art,
• collection,
• image,
• rod,
• ceiling,
• lighting,
• fee,
• underside,
• stone,
• tissue,
• tool,
• embellishment,
• food,
• section,
• card,
• record,
• stick,
• form,
• painting,
• sign,
• cookware,
• web,
• condition,
• plane,
• space,
• strip,
• shield,
• artwork,
• facility,
• document,
• mold,
• blade,
• plate,
• work,
• figure,
• member,
• product,
• paper,
• land,
• segment,
• road,
• dish,
• upland,
• structure,
• original,
• medium,
• cloth,
• vehicle,
• tin,
• device,
• mirror,
• sheet,
• drawing,
• foot,
• portion,
• package,
• display,
• fabric,
• design,
• bottle,
• earth,
• feature,
• blank,
• wall,
• ornament,
• base,
• body,
• course,
• gasket,
• thing,
• seal,
• artifact,
• ride,
• topology,
• equipment,
• muscle,
• flower,
• part,
• pad,
• linen,
• glass,
• bottom,
• creature,
• content,
• ribbon,
• abstraction,
• conductor,
• circuit,
• speaker,
• substance,
• tableware,
• slab,
• block,
• x-ray,
• particle,
• clothing,
• rock,
• crystal,
• instrument,
• option,
• waveform,
• floor,
• terrain,
• foliage,
• deck,
• piece,
• implement,
• copy,
• specimen,
• subject,
• works,
• footwear,
• furniture,
• string,